| Year |
Citation |
Score |
| 2020 |
Antoni PW, Mackenroth AV, Mulks FF, Rudolph M, Helmchen G, Hashmi ASK. Dibenzothiophenesulfilimines: A Convenient Approach to Intermolecular Rhodium-Catalysed C-H Amination. Chemistry (Weinheim An Der Bergstrasse, Germany). PMID 32428332 DOI: 10.1002/Chem.202002371 |
0.333 |
|
| 2020 |
Helmchen G. Discussion Addendum for: Dibenzo[a,e]cyclooctene: Multigram Synthesis of a Bidentate Ligand Organic Syntheses. 97: 66-78. DOI: 10.15227/Orgsyn.097.0066 |
0.34 |
|
| 2018 |
Cheng Q, Tu HF, Zheng C, Qu JP, Helmchen G, You SL. Iridium-Catalyzed Asymmetric Allylic Substitution Reactions. Chemical Reviews. PMID 30582688 DOI: 10.1021/Acs.Chemrev.8B00506 |
0.438 |
|
| 2017 |
Qu J, Helmchen G. Applications of Iridium-Catalyzed Asymmetric Allylic Substitution Reactions in Target-Oriented Synthesis. Accounts of Chemical Research. PMID 28937739 DOI: 10.1021/Acs.Accounts.7B00300 |
0.5 |
|
| 2016 |
Seehafer K, Malakar CC, Bender M, Qu J, Liang C, Helmchen G. Iridium-catalyzed asymmetric allylic substitutions with bulky amines/oxidative double bond cleavage - Entry into the reetz synthesis of amino alcohols European Journal of Organic Chemistry. 2016: 493-501. DOI: 10.1002/Ejoc.201501333 |
0.438 |
|
| 2015 |
Malakar CC, Helmchen G. Immobilized catalysts for iridium-catalyzed allylic amination: rate enhancement by immobilization. Chemistry (Weinheim An Der Bergstrasse, Germany). 21: 7127-34. PMID 25787122 DOI: 10.1002/Chem.201500382 |
0.325 |
|
| 2014 |
Qu J, Roßberg L, Helmchen G. Enantio- and regioselective iridium-catalyzed allylic esterification. Journal of the American Chemical Society. 136: 1272-5. PMID 24422670 DOI: 10.1021/Ja411869R |
0.462 |
|
| 2014 |
Satyanarayana G, Helmchen G. Enantioselective syntheses of bicyclic lactams based on iridium-catalyzed asymmetric allylic substitution and heck cyclization European Journal of Organic Chemistry. 2014: 2242-2252. DOI: 10.1002/Ejoc.201301813 |
0.678 |
|
| 2014 |
Helmchen G. Ir-Catalyzed Asymmetric Allylic Substitution Reactions - Fundamentals and Applications in Natural Products Synthesis Molecular Catalysts: Structure and Functional Design. 239-254. DOI: 10.1002/9783527673278.ch11 |
0.334 |
|
| 2013 |
Jäkel M, Qu J, Schnitzer T, Helmchen G. Addition of organometallic reagents to chiral N-methoxylactams: enantioselective syntheses of pyrrolidines and piperidines. Chemistry (Weinheim An Der Bergstrasse, Germany). 19: 16746-55. PMID 24151151 DOI: 10.1002/Chem.201302735 |
0.475 |
|
| 2013 |
Seehafer K, Rominger F, Helmchen G, Langhans M, Robinson DG, Özata B, Brügger B, Strating JR, van Kuppeveld FJ, Klein CD. Synthesis and biological properties of novel brefeldin A analogues. Journal of Medicinal Chemistry. 56: 5872-84. PMID 23805957 DOI: 10.1021/Jm400615G |
0.367 |
|
| 2013 |
Gärtner M, Satyanarayana G, Förster S, Helmchen G. Syntheses of the hexahydroindene cores of indanomycin and stawamycin by combinations of iridium-catalyzed asymmetric allylic alkylations and intramolecular Diels-Alder reactions. Chemistry (Weinheim An Der Bergstrasse, Germany). 19: 400-5. PMID 23180592 DOI: 10.1002/Chem.201202822 |
0.663 |
|
| 2013 |
Hoecker J, Rudolf GC, Bächle F, Fleischer S, Lindner BD, Helmchen G. Enantio- and diastereoselective syntheses of 3-hydroxypiperidines through iridium-catalyzed allylic substitution European Journal of Organic Chemistry. 5149-5159. DOI: 10.1002/Ejoc.201300445 |
0.486 |
|
| 2012 |
Raskatov JA, Jäkel M, Straub BF, Rominger F, Helmchen G. Iridium-catalyzed allylic substitutions with cyclometalated phosphoramidite complexes bearing a dibenzocyclooctatetraene ligand: preparation of (π-allyl)Ir complexes and computational and NMR spectroscopic studies. Chemistry (Weinheim An Der Bergstrasse, Germany). 18: 14314-28. PMID 23018807 DOI: 10.1002/Chem.201201772 |
0.431 |
|
| 2012 |
Gärtner M, Kossler D, Pflästerer D, Helmchen G. Enantioselective total synthesis and absolute configuration of apiosporic acid. The Journal of Organic Chemistry. 77: 4491-5. PMID 22510063 DOI: 10.1021/Jo300519G |
0.436 |
|
| 2012 |
Gärtner M, Qu J, Helmchen G. Enantioselective syntheses of the alkaloids cis-195A (pumiliotoxin C) and trans-195A based on multiple applications of asymmetric catalysis. The Journal of Organic Chemistry. 77: 1186-90. PMID 22175856 DOI: 10.1021/Jo202241B |
0.371 |
|
| 2012 |
Franck G, Brill M, Helmchen G. Dibenzo[a,e]cyclooctene: Multi-gram synthesis of a bidentate ligand Organic Syntheses. 89: 55-65. DOI: 10.1002/0471264229.Os089.05 |
0.307 |
|
| 2011 |
Ye KY, He H, Liu WB, Dai LX, Helmchen G, You SL. Iridium-catalyzed allylic vinylation and asymmetric allylic amination reactions with o-aminostyrenes. Journal of the American Chemical Society. 133: 19006-14. PMID 21995503 DOI: 10.1021/Ja2092954 |
0.448 |
|
| 2011 |
Gärtner M, Weihofen R, Helmchen G. Enantioselective syntheses of 2,5-disubstituted pyrrolidines based on iridium-catalyzed allylic aminations--total syntheses of alkaloids from amphibian skins. Chemistry (Weinheim An Der Bergstrasse, Germany). 17: 7605-22. PMID 21611991 DOI: 10.1002/Chem.201100649 |
0.473 |
|
| 2011 |
Gärtner M, Jäkel M, Achatz M, Sonnenschein C, Tverskoy O, Helmchen G. Enantioselective iridium-catalyzed allylic substitutions with hydroxamic acid derivatives as N-nucleophiles. Organic Letters. 13: 2810-3. PMID 21534551 DOI: 10.1021/Ol200688D |
0.481 |
|
| 2011 |
Gärtner M, Mader S, Seehafer K, Helmchen G. Enantio- and regioselective iridium-catalyzed allylic hydroxylation. Journal of the American Chemical Society. 133: 2072-5. PMID 21275067 DOI: 10.1021/Ja109953V |
0.405 |
|
| 2011 |
Gärtner M, Jäkel M, Achatz M, Sonnenschein C, Tverskoy O, Helmchen G. Enantioselective Allylic Substitutions with Hydroxamic AcidDerivatives Synfacts. 2011: 1098-1098. DOI: 10.1055/S-0030-1261126 |
0.482 |
|
| 2011 |
Satyanarayana G, Pflästerer D, Helmchen G. Enantioselective syntheses of tetrahydroquinolines based on iridium-catalyzed allylic substitutions: Total syntheses of (+)-angustureine and (-)-cuspareine European Journal of Organic Chemistry. 6877-6886. DOI: 10.1002/Ejoc.201100981 |
0.68 |
|
| 2011 |
Förster S, Persch E, Tverskoy O, Rominger F, Helmchen G, Klein C, Gönen B, Brügger B. Syntheses and biological properties of brefeldin analogues European Journal of Organic Chemistry. 878-891. DOI: 10.1002/Ejoc.201001297 |
0.394 |
|
| 2011 |
Farwick A, Engelhart JU, Tverskoy O, Welter C, Umlauf Née Stang QA, Rominger F, Kerr WJ, Helmchen G. Bicyclic cyclopentenones via the combination of an iridium-catalyzed allylic substitution with a diastereoselective intramolecular pauson-khand reaction Advanced Synthesis and Catalysis. 353: 349-370. DOI: 10.1002/Adsc.201000706 |
0.486 |
|
| 2011 |
Raskatov JA, Helmchen G. Effects of Substituents on the Regioselectivity of Palladium-Catalyzed Allylic Substitutions: A DFT Study Modeling of Molecular Properties. 191-206. DOI: 10.1002/9783527636402.ch12 |
0.351 |
|
| 2010 |
Schelwies M, Farwick A, Rominger F, Helmchen G. Platinum(II) chloride-catalyzed stereoselective domino enyne isomerization/Diels-Alder reaction. The Journal of Organic Chemistry. 75: 7917-9. PMID 20958079 DOI: 10.1021/Jo1014068 |
0.444 |
|
| 2010 |
Franck G, Brödner K, Helmchen G. Enantioselective modular synthesis of cyclohexenones: total syntheses of (+)-crypto- and (+)-infectocaryone. Organic Letters. 12: 3886-9. PMID 20677804 DOI: 10.1021/Ol101588J |
0.479 |
|
| 2010 |
Raskatov JA, Spiess S, Gnamm C, Brödner K, Rominger F, Helmchen G. Ir-catalysed asymmetric allylic substitutions with cyclometalated (phosphoramidite)Ir complexes--resting states, catalytically active (pi-allyl)Ir complexes and computational exploration. Chemistry (Weinheim An Der Bergstrasse, Germany). 16: 6601-15. PMID 20419716 DOI: 10.1002/Chem.200903465 |
0.394 |
|
| 2010 |
Farwick A, Helmchen G. Enantioselective total synthesis of (-)-alpha-kainic acid. Organic Letters. 12: 1108-11. PMID 20148523 DOI: 10.1021/Ol1001076 |
0.432 |
|
| 2010 |
Franck G, Brödner K, Helmchen G. Enantioselective Synthesis of Cyclohexenones Synfacts. 2010: 1166-1166. DOI: 10.1055/S-0030-1258649 |
0.466 |
|
| 2010 |
HELMCHEN G, KROTZ A, NEUMANN H, ZIEGLER ML. ChemInform Abstract: Enantiomerically Pure Chiral Building Blocks for Syntheses of Carbocyclic Nucleoside Analogues: A Formal Synthesis of Aristeromycin. Cheminform. 25: no-no. DOI: 10.1002/CHIN.199414280 |
0.35 |
|
| 2010 |
HAMLEY P, HELMCHEN G, HOLMES AB, MARSHALL DR, MACKINNON JWM, SMITH DF, ZILLER JW. ChemInform Abstract: Diastereoselective Imino Ester Cycloadditions. Enantioselective Synthesis of Azabicyclo(2.2.1)heptenes. Cheminform. 23: no-no. DOI: 10.1002/chin.199242180 |
0.393 |
|
| 2010 |
Farwick A, Helmchen G. Stereoselective Synthesis of β-Proline Derivatives from Allylamines via Domino Hydroformylation/Wittig Olefination and Aza-Michael Addition Advanced Synthesis & Catalysis. 352: 1023-1032. DOI: 10.1002/Adsc.201000016 |
0.423 |
|
| 2009 |
Spiess S, Raskatov JA, Gnamm C, Brödner K, Helmchen G. Ir-Catalyzed asymmetric allylic substitutions with (phosphoramidite)Ir complexes-resting states, synthesis, and characterization of catalytically active (pi-allyl)Ir complexes. Chemistry (Weinheim An Der Bergstrasse, Germany). 15: 11087-90. PMID 19750530 DOI: 10.1002/Chem.200902065 |
0.388 |
|
| 2009 |
Schelwies M, Moser R, Dempwolff AL, Rominger F, Helmchen G. Gold-catalyzed intermolecular addition of carbonyl compounds to 1,6-enynes: reactivity, scope, and mechanistic aspects. Chemistry (Weinheim An Der Bergstrasse, Germany). 15: 10888-900. PMID 19746480 DOI: 10.1002/Chem.200901614 |
0.415 |
|
| 2009 |
Gnamm C, Brödner K, Krauter CM, Helmchen G. A configurational switch based on iridium-catalyzed allylic cyclization: application in asymmetric total syntheses of prosopis, dendrobate, and spruce alkaloids. Chemistry (Weinheim An Der Bergstrasse, Germany). 15: 10514-32. PMID 19731272 DOI: 10.1002/Chem.200901316 |
0.473 |
|
| 2009 |
Gnamm C, Krauter CM, Brödner K, Helmchen G. Stereoselective synthesis of 2,6-disubstituted piperidines using the iridium-catalyzed allylic cyclization as configurational switch: asymmetric total synthesis of (+)-241 d and related piperidine alkaloids. Chemistry (Weinheim An Der Bergstrasse, Germany). 15: 2050-4. PMID 19180605 DOI: 10.1002/chem.200802525 |
0.316 |
|
| 2009 |
Dübon P, Farwick A, Helmchen G. Enantioselective syntheses of 2-substituted pyrrolidines from allylamines by domino hydroformylation-condensation: Short syntheses of (S)-nicotine and the alkaloid 225C Synlett. 1413-1416. DOI: 10.1055/S-0029-1217165 |
0.439 |
|
| 2009 |
Gnamn C, Krauter CM, Brödner K, Helmchen G. Iridium-Catalyzed Asymmetric Synthesis of 2,6-DisubstitutedPiperidines Synfacts. 2009: 520-520. DOI: 10.1055/S-0029-1216623 |
0.478 |
|
| 2008 |
Spiess S, Welter C, Franck G, Taquet JP, Helmchen G. Iridium-catalyzed asymmetric allylic substitutions--very high regioselectivity and air stability with a catalyst derived from dibenzo[a,e]cyclooctatetraene and a phosphoramidite. Angewandte Chemie (International Ed. in English). 47: 7652-5. PMID 18767095 DOI: 10.1002/Anie.200802480 |
0.388 |
|
| 2008 |
Dübon P, Schelwies M, Helmchen G. Preparation of 2,4-disubstituted cyclopentenones by enantioselective iridium-catalyzed allylic alkylation: synthesis of 2'-methylcarbovir and TEI-9826. Chemistry (Weinheim An Der Bergstrasse, Germany). 14: 6722-33. PMID 18576413 DOI: 10.1002/chem.200800495 |
0.396 |
|
| 2008 |
Förster S, Helmchen G. Stereoselective synthesis of a lactam analogue of brefeldin C Synlett. 831-836. DOI: 10.1055/S-2008-1042899 |
0.391 |
|
| 2008 |
Spiess S, Welter C, Franck G, Taquet J-, Helmchen G. Air-Stable Iridium Catalyst in Asymmetric Allylic Substitution Synfacts. 2008: 1303-1303. DOI: 10.1055/S-0028-1087320 |
0.355 |
|
| 2008 |
Förster S, Tverskoy O, Helmchen G. Malononitrile as acylanion equivalent Synlett. 2803-2806. DOI: 10.1055/S-0028-1083540 |
0.391 |
|
| 2008 |
Gnamm C, Franck G, Miller N, Stork T, Brödner K, Helmchen G. Enantioselective iridium-catalyzed allylic aminations of allylic carbonates with functionalized side chains. Asymmetric total synthesis of (S)-vigabatrin Synthesis. 3331-3350. DOI: 10.1055/S-0028-1083158 |
0.403 |
|
| 2008 |
Elsner P, Jetter P, Brödner K, Helmchen G. Stereoselective synthesis of a cis-1,2-dialkylcyclopentane building block and its application in isoprostane synthesis (5-ent-F2c-IsoP) European Journal of Organic Chemistry. 2551-2563. DOI: 10.1002/Ejoc.200800010 |
0.441 |
|
| 2007 |
Spiess S, Berthold C, Weihofen R, Helmchen G. Synthesis of alpha,beta-unsaturated gamma-lactams via asymmetric iridium-catalysed allylic substitution. Organic & Biomolecular Chemistry. 5: 2357-60. PMID 17637953 DOI: 10.1039/B708571K |
0.371 |
|
| 2007 |
Schelwies M, Dempwolff AL, Rominger F, Helmchen G. Gold-catalyzed intermolecular addition of carbonyl compounds to 1,6-enynes. Angewandte Chemie (International Ed. in English). 46: 5598-601. PMID 17583886 DOI: 10.1002/Anie.200701378 |
0.355 |
|
| 2007 |
Helmchen G, Dahnz A, Dübon P, Schelwies M, Weihofen R. Iridium-catalysed asymmetric allylic substitutions. Chemical Communications (Cambridge, England). 675-91. PMID 17392951 DOI: 10.1039/b614169b |
0.342 |
|
| 2007 |
Schelwies M, Dempwolff AL, Rominger F, Helmchen G. Gold-Catalyzed Addition of Aldehydes to 1,6-Enynes Synfacts. 2007: 1166-1166. DOI: 10.1055/S-2007-991272 |
0.391 |
|
| 2007 |
Gnamm C, Förster S, Miller N, Brödner K, Helmchen G. Enantioselective Iridium-catalyzed allylic alkylations - Improvements and applications based on salt-free reaction conditions Synlett. 790-794. DOI: 10.1055/S-2007-970754 |
0.471 |
|
| 2007 |
Gnamm C, Förster S, Miller N, Brödner K, Helmchen G. Salt-Free Enantioselective Iridium-Catalyzed Allylic Alkylations Synfacts. 2007: 627-627. DOI: 10.1055/S-2007-968503 |
0.447 |
|
| 2007 |
Schelwies M, Dempwolff AL, Rominger F, Helmchen G. Gold‐katalysierte intermolekulare Addition von Carbonylverbindungen an 1,6‐Enine Angewandte Chemie. 119: 5694-5697. DOI: 10.1002/Ange.200701378 |
0.319 |
|
| 2006 |
Weihofen R, Tverskoy O, Helmchen G. Salt-free iridium-catalyzed asymmetric allylic aminations with N,N-diacylamines and ortho-nosylamide as ammonia equivalents. Angewandte Chemie (International Ed. in English). 45: 5546-9. PMID 16856193 DOI: 10.1002/Anie.200601472 |
0.332 |
|
| 2006 |
Geisler FM, Helmchen G. Chiral phosphinooxazolines with a pentamethylferrocene backbone--synthesis and use as ligands in asymmetric catalysis. The Journal of Organic Chemistry. 71: 2486-92. PMID 16526801 DOI: 10.1021/jo0526136 |
0.31 |
|
| 2006 |
Schelwies M, Dübon P, Helmchen G. Enantioselective modular synthesis of 2,4-disubstituted cyclopentenones by iridium-catalyzed allylic alkylation. Angewandte Chemie (International Ed. in English). 45: 2466-9. PMID 16526068 DOI: 10.1002/Anie.200503945 |
0.509 |
|
| 2006 |
Weihofen R, Tverskoy O, Helmchen G. Enantioselective Allylic Aminations Synfacts. 2006: 1133-1133. DOI: 10.1055/S-2006-949449 |
0.489 |
|
| 2006 |
Geisler FM, Helmchen G. A straightforward synthesis of (3S)-4-methoxybutane-1,3-diol and its use as chiral auxiliary for the preparation of (p5)-1-(diphenylphosphino)-2-formyl- 1′,2′,3′,4′,5′-pentamethylferrocene Synthesis. 2201-2205. DOI: 10.1055/s-2006-942415 |
0.303 |
|
| 2006 |
Hübscher T, Helmchen G. Enantioselective formal synthesis of brefeldin A and analogues via anionic cyclization of an alkenyl epoxide Synlett. 1323-1326. DOI: 10.1055/S-2006-941575 |
0.496 |
|
| 2006 |
Dahnz A, Helmchen G. Enantioselective Allylic Substitutions with Aliphatic Nitro Compounds Synfacts. 2006: 469-469. DOI: 10.1055/S-2006-934444 |
0.404 |
|
| 2006 |
Dahnz A, Helmchen G. Iridium-catalyzed enantioselective allylic substitutions with aliphatic nitro compounds as prenucleophiles Synlett. 697-700. DOI: 10.1055/S-2006-933121 |
0.47 |
|
| 2006 |
Becht J-, Bappert E, Helmchen G. N-Heterocyclic Carbenes for Conjugate Additions of Arylboronic Acids Synfacts. 2006: 39-39. DOI: 10.1055/S-2005-921740 |
0.324 |
|
| 2006 |
Welter C, Moreno RM, Streiff S, Helmchen G. Synthesis of (+)(R)- and (-)(S)-Nicotine via Enantioselective Ir-Catalyzed Allylic Amination Synfacts. 2006: 29-29. DOI: 10.1055/S-2005-921694 |
0.389 |
|
| 2006 |
Schelwies M, Dübon P, Helmchen G. Enantioselektive modulare Synthese von 2,4‐disubstituierten Cyclopentenonen durch Iridium‐katalysierte allylische Alkylierung Angewandte Chemie. 118: 2526-2529. DOI: 10.1002/Ange.200503945 |
0.406 |
|
| 2006 |
Prelog V, Helmchen G. Grundlagen des CIP‐Systems und Vorschläge für eine Revision Angewandte Chemie. 94: 614-631. DOI: 10.1002/Ange.19820940805 |
0.504 |
|
| 2005 |
Welter C, Moreno RM, Streiff S, Helmchen G. Enantioselective synthesis of (+)(R)- and (-)(S)-nicotine based on Ir-catalysed allylic amination. Organic & Biomolecular Chemistry. 3: 3266-8. PMID 16132087 DOI: 10.1039/B508634E |
0.418 |
|
| 2005 |
Weihofen R, Dahnz A, Tverskoy O, Helmchen G. Highly enantioselective iridium-catalysed allylic aminations with anionic N-nucleophiles. Chemical Communications (Cambridge, England). 3541-3. PMID 16010317 DOI: 10.1039/B505197E |
0.414 |
|
| 2005 |
Streiff S, Welter C, Schelwies M, Lipowsky G, Miller N, Helmchen G. Carbocycles via enantioselective inter- and intramolecular iridium-catalysed allylic alkylations. Chemical Communications (Cambridge, England). 2957-9. PMID 15957038 DOI: 10.1039/b503713a |
0.361 |
|
| 2005 |
Welter C, Dahnz A, Brunner B, Streiff S, Dübon P, Helmchen G. Highly enantioselective syntheses of heterocycles via intramolecular Ir-catalyzed allylic amination and etherification. Organic Letters. 7: 1239-42. PMID 15787476 DOI: 10.1021/Ol047351T |
0.478 |
|
| 2005 |
Welter C, Dahnz A, Brunner B, Streiff S, Dübon P, Helmchen G. Ir-Catalyzed Allylic Amination and Etherification Synfacts. 2005: 35-35. DOI: 10.1055/S-2005-869912 |
0.43 |
|
| 2005 |
Stang AQ, Helmchen G. Enantioselective syntheses and fragrance properties of the four stereoisomers of Magnolione® (magnolia ketone) Helvetica Chimica Acta. 88: 2738-2746. DOI: 10.1002/Hlca.200590213 |
0.398 |
|
| 2005 |
Wiese B, Knühl G, Flubacher D, Prieß JW, Ulriksen B, Brödner K, Helmchen G. Syntheses of new chiral phosphane ligands by diastereoselective conjugate addition of phosphides to enantiomerically pure acceptor-substituted olefins from the chiral pool European Journal of Organic Chemistry. 3246-3262. DOI: 10.1002/Ejoc.200500144 |
0.479 |
|
| 2005 |
Becht JM, Bappert E, Helmchen G. Application of rhodium complexes of chiral diphenylphosphino-functionalized N-heterocyclic carbenes as catalysts in enantioselective conjugate additions of arylboronic acids Advanced Synthesis and Catalysis. 347: 1495-1498. DOI: 10.1002/Adsc.200404327 |
0.431 |
|
| 2004 |
Welter C, Koch O, Lipowsky G, Helmchen G. First intramolecular enantioselective iridium-catalysed allylic aminations. Chemical Communications (Cambridge, England). 896-7. PMID 15045118 DOI: 10.1039/B400023D |
0.422 |
|
| 2004 |
Korff C, Helmchen G. Preparation of chiral triarylphosphines by Pd-catalysed asymmetric P-C cross-coupling. Chemical Communications (Cambridge, England). 530-1. PMID 14973592 DOI: 10.1039/B315009G |
0.347 |
|
| 2004 |
Lipowsky G, Helmchen G. Regio- and enantioselective iridium-catalysed allylic aminations and alkylations of dienyl esters. Chemical Communications (Cambridge, England). 116-7. PMID 14737359 DOI: 10.1039/B311502J |
0.451 |
|
| 2004 |
Helmchen G, Ernst M, Paradies G. Application of allylic Substitutions in natural products synthesis Pure and Applied Chemistry. 76: 495-506. DOI: 10.1351/Pac200476030495 |
0.471 |
|
| 2004 |
Bappert E, Helmchen G. Synthesis and application of complexes of a novel chiral diphenylphosphino-functionalized N-heterocyclic carbene Synlett. 1789-1793. DOI: 10.1055/S-2004-829548 |
0.395 |
|
| 2004 |
García-Yebra C, Janssen JP, Rominger F, Helmchen G. Asymmetric iridium(I)-catalyzed allylic alkylation of monosubstituted allylic substrates with phosphinooxazolines as ligands. isolation, characterization, and reactivity of chiral (allyl)iridium(III) complexes Organometallics. 23: 5459-5470. DOI: 10.1021/Om0401105 |
0.419 |
|
| 2003 |
Montenegro E, Gabler B, Paradies G, Seemann M, Helmchen G. Determination of the configuration of an archaea membrane lipid containing cyclopentane rings by total synthesis. Angewandte Chemie (International Ed. in English). 42: 2419-21. PMID 12783513 DOI: 10.1002/Anie.200250629 |
0.301 |
|
| 2003 |
Becht JM, Meyer O, Helmchen G. Enantioselective Syntheses of (-)-(R)-Rolipram, (-)-(R)-Baclofen and Other GABA Analogues via Rhodium-Catalyzed Conjugate Addition of Arylboronic Acids Synthesis. 2805-2810. DOI: 10.1055/S-2003-42457 |
0.345 |
|
| 2003 |
Meyer O, Becht JM, Helmchen G. Enantioselective synthesis of (-)-(R)-Baclofen and analogues via rhodium-catalysed conjugate addition of boronic acids Synlett. 1539-1541. DOI: 10.1055/S-2003-40847 |
0.395 |
|
| 2003 |
Bartels B, García-Yebra C, Helmchen G. Asymmetric IrI-catalysed allylic alkylation of monosubstituted allylic acetates with phosphorus amidites as ligands European Journal of Organic Chemistry. 1097-1103. DOI: 10.1002/Ejoc.200390162 |
0.496 |
|
| 2003 |
Ostermeier M, Brunner B, Korff C, Helmchen G. Highly Enantioselective Rhodium‐Catalyzed Hydrogenation of 2‐(2‐Methoxy‐2‐oxoethyl)acrylic Acid − A Convenient Access of Enantiomerically Pure Isoprenoid Building Blocks European Journal of Organic Chemistry. 2003: 3453-3459. DOI: 10.1002/Ejoc.200300222 |
0.436 |
|
| 2003 |
Seemann M, Schöller M, Kudis S, Helmchen G. Syntheses of enantiomerically pure cyclopent-2-ene-1-carboxylic acid and (cyclopent-2-enyl)acetic acid by enantioselective palladium-catalyzed allylic alkylations - Synthesis of enantiomerically pure (-)-chaulmoogric acid European Journal of Organic Chemistry. 2122-2127. DOI: 10.1002/Ejoc.200200700 |
0.428 |
|
| 2002 |
Ernst M, Helmchen G. A new synthesis route to enantiomerically pure jasmonoids. Angewandte Chemie (International Ed. in English). 41: 4054-6. PMID 12412079 DOI: 10.1002/1521-3773(20021104)41:21<4054::Aid-Anie4054>3.0.Co;2-K |
0.406 |
|
| 2002 |
Kollmar M, Steinhagen H, Janssen JP, Goldfuss B, Malinovskaya SA, Vázquez J, Rominger F, Helmchen G. (Eta3-phenylallyl)(phosphanyloxazoline)palladium complexes: X-ray crystallographic studies, NMR investigations, and Ab initio/DFT calculations. Chemistry (Weinheim An Der Bergstrasse, Germany). 8: 3103-14. PMID 12203340 DOI: 10.1002/1521-3765(20020715)8:14<3103::Aid-Chem3103>3.0.Co;2-C |
0.358 |
|
| 2002 |
Weiss TD, Helmchen G, Kazmaier U. Synthesis of amino acid derivatives via enantio- and diastereoselective Pd-catalyzed allylic substitutions with a non-stabilized enolate as nucleophile. Chemical Communications (Cambridge, England). 1270-1. PMID 12109110 DOI: 10.1039/B203791M |
0.415 |
|
| 2002 |
Ernst M, Helmchen G. A novel route to iridoids: Enantioselective syntheses of isoiridomyrmecin and α-skytanthine Synthesis. 1953-1955. DOI: 10.1055/S-2002-34382 |
0.39 |
|
| 2002 |
Kollmar M, Helmchen G. An (η1-allyl) palladium complex of a chiral bidentate ligand: Crystallographic and NMR studies on a (η1-3,3-diphenylallyl)(phosphinooxazoline) palladium complex Organometallics. 21: 4771-4775. DOI: 10.1021/Om020323Z |
0.369 |
|
| 2002 |
Ostermeier M, Prieß J, Helmchen G. Mono- and bidentate phosphinanes - New chiral ligands and their application in catalytic asymmetric hydrogenations Angewandte Chemie - International Edition. 41: 612-614. DOI: 10.1002/1521-3773(20020215)41:4<612::Aid-Anie612>3.0.Co;2-9 |
0.36 |
|
| 2002 |
Ostermeier M, Prieß J, Helmchen G. Ein‐ und zweizähnige Phosphinane – neue chirale Liganden und ihr Einsatz in der katalytischen asymmetrischen Hydrierung Angewandte Chemie. 114: 625-628. DOI: 10.1002/1521-3757(20020215)114:4<625::Aid-Ange625>3.0.Co;2-E |
0.373 |
|
| 2002 |
Bartels B, García-Yebra C, Rominger F, Helmchen G. Iridium-catalysed allylic substitution: Stereochemical aspects and isolation of IrIII complexes related to the catalytic cycle European Journal of Inorganic Chemistry. 2569-2586. DOI: 10.1002/1099-0682(200210)2002:10<2569::Aid-Ejic2569>3.0.Co;2-5 |
0.443 |
|
| 2002 |
Kollmar M, Parlitz R, Stephan R, Helmchen G, Li H, Miller MJ. 2-amino-3-fluorobenzoic acid Organic Syntheses. 79: 196-203. DOI: 10.1002/0471264180.Os079.23 |
0.346 |
|
| 2001 |
Volland MAO, Kudis S, Helmchen G, Hyla-Kryspin I, Rominger aF, Gleiter R. Structure and Bonding Properties of the Complex (η5-Diphenylfulvene)Mn(CO)3+ Organometallics. 20: 227-230. DOI: 10.1021/Om000587Q |
0.334 |
|
| 2000 |
Bergner EJ, Helmchen G. Enantioselective synthesis of (+)-juvabione. The Journal of Organic Chemistry. 65: 5072-4. PMID 10956500 DOI: 10.1021/Jo005516F |
0.464 |
|
| 2000 |
Bergner EJ, Helmchen G. Synthesis of enantiomerically pure (-)-wine lactone based on a palladium-catalyzed enantioselective allylic substitution European Journal of Organic Chemistry. 419-423. DOI: 10.1002/(Sici)1099-0690(200002)2000:3<419::Aid-Ejoc419>3.0.Co;2-N |
0.465 |
|
| 1999 |
Bartels B, Helmchen G. Ir-catalysed allylic substitution: Mechanistic aspects and asymmetric synthesis with phosphorus amidites as ligands Chemical Communications. 741-742. DOI: 10.1039/A900864K |
0.436 |
|
| 1999 |
Flubacher D, Helmchen G. Enantioselective domino heck-allylic amination reactions Tetrahedron Letters. 40: 3867-3868. DOI: 10.1016/S0040-4039(99)00628-0 |
0.435 |
|
| 1999 |
Helmchen G. Enantioselective palladium-catalyzed allylic substitutions with asymmetric chiral ligands Journal of Organometallic Chemistry. 576: 203-214. DOI: 10.1016/S0022-328X(98)01059-6 |
0.423 |
|
| 1999 |
Schleich S, Helmchen G. Pd‐Catalyzed Asymmetric Allylic Alkylation of 3‐Acetoxy‐N‐(tert‐butyloxycarbonyl)‐1,2,3,6‐tetrahydropyridine – Preparation of Key Intermediates for Natural Product Synthesis European Journal of Organic Chemistry. 1999: 2515-2521. DOI: 10.1002/(Sici)1099-0690(199910)1999:10<2515::Aid-Ejoc2515>3.0.Co;2-G |
0.468 |
|
| 1998 |
Kudis S, Helmchen G. Enantioselective Allylic Substitution of Cyclic Substrates by Catalysis with Palladium Complexes of P,N-Chelate Ligands with a Cymantrene Unit. Angewandte Chemie (International Ed. in English). 37: 3047-3050. PMID 29711133 DOI: 10.1002/(Sici)1521-3773(19981116)37:21<3047::Aid-Anie3047>3.0.Co;2-J |
0.388 |
|
| 1998 |
Johannsen M, Anker Jorgensen K, Helmchen G. Synthesis and application of the first chiral and highly Lewis acidic silyl cationic catalyst Journal of the American Chemical Society. 120: 7637-7638. DOI: 10.1021/Ja981021K |
0.385 |
|
| 1998 |
Wiese B, Helmchen G. Chiral phosphinooxazolines with a Bi- or tricyclic oxazoline moiety - Applications in Pd-catalyzed allylic alkylations Tetrahedron Letters. 39: 5727-5730. DOI: 10.1016/S0040-4039(98)01173-3 |
0.392 |
|
| 1998 |
Sagasser I, Helmchen G. (Phosphino-oxazoline)copper(II) complexes as chiral catalysts for enantioselective Diels-Alder reactions Tetrahedron Letters. 39: 261-264. DOI: 10.1016/S0040-4039(97)10570-6 |
0.388 |
|
| 1998 |
Kudis S, Helmchen G. First enantioselective synthesis of (+)-(3R,3aS,6aS)-3-hydroxy- 3,3a,4,6a-tetrahydrocyclopenta[b] furan-2-one - A versatile chiral heterocyclic building block Tetrahedron. 54: 10449-10456. DOI: 10.1016/S0040-4020(98)00497-9 |
0.314 |
|
| 1997 |
Helmchen G, Kudis S, Sennhenn P, Steinhagen H. Enantioselective catalysis with complexes of asymmetric P,N-chelate ligands Pure and Applied Chemistry. 69: 513-518. DOI: 10.1351/Pac199769030513 |
0.324 |
|
| 1997 |
Bilz A, Stork T, Helmchen G. New chiral solvating agents for carboxylic acids: Discrimination of enantiotopic nuclei and binding properties Tetrahedron Asymmetry. 8: 3999-4002. DOI: 10.1016/S0957-4166(97)00586-7 |
0.33 |
|
| 1997 |
Janssen JP, Helmchen G. First enantioselective alkylations of monosubstituted allylic acetates catalyzed by chiral iridium complexes Tetrahedron Letters. 38: 8025-8026. DOI: 10.1016/S0040-4039(97)10220-9 |
0.45 |
|
| 1997 |
Steinhagen H, Reggelin M, Helmchen G. Palladium-catalyzed allylic alkylation with phosphinoaryldihydrooxazole ligands: First evidence and NMR spectroscopic structure determination of a primary olefin-Pd0 complex Angewandte Chemie - International Edition in English. 36: 2108-2110. DOI: 10.1002/Anie.199721081 |
0.341 |
|
| 1996 |
Langer T, Illich M, Helmchen G. Diastereoselective Oxidative Coupling of Enolates of 3-Phenylpropionic Acid Derivatives - EPC Synthesis of ent-Hinokinin Synlett. 1996: 1137-1139. DOI: 10.1055/S-1996-5668 |
0.367 |
|
| 1996 |
Langer T, Janssen J, Helmchen G. Catalytic asymmetric hydrosilylation of ketones using rhodium-(I)-complexes of chiral phosphinooxazoline ligands Tetrahedron Asymmetry. 7: 1599-1602. DOI: 10.1016/0957-4166(96)00192-9 |
0.399 |
|
| 1996 |
Langer T, Helmchen G. Highly efficient new catalysts for enantioselective transfer hydrogenation of ketones Tetrahedron Letters. 37: 1381-1384. DOI: 10.1016/0040-4039(96)00011-1 |
0.385 |
|
| 1996 |
Peer M, De Jong JC, Kiefer M, Langer T, Rieck H, Schell H, Sennhenn P, Sprinz J, Steinhagen H, Wiese B, Helmchen G. Preparation of chiral phosphorus, sulfur and selenium containing 2-aryloxazolines Tetrahedron. 52: 7547-7583. DOI: 10.1016/0040-4020(96)00267-0 |
0.448 |
|
| 1996 |
Urban E, Knühl G, Helmchen G. Enantiomerically pure 5-substituted 2-oxo-cyclopentanecarboxylates by conjugate addition of cuprates to asymmetric shielded 2-oxo-cyclopentenecarboxylates Tetrahedron. 52: 971-986. DOI: 10.1016/0040-4020(95)00951-5 |
0.378 |
|
| 1996 |
Steinhagen H, Helmchen G. Asymmetric Two‐Center Catalysis—Learning from Nature Angewandte Chemie. 35: 2339-2342. DOI: 10.1002/Anie.199623391 |
0.324 |
|
| 1996 |
Rieck H, Helmchen G. Palladium complex catalyzed asymmetric allylic substitutions with nitromethane: Enantioselectivities exceeding 99.9% ee Angewandte Chemie (International Edition in English). 34: 2687-2689. DOI: 10.1002/Anie.199526871 |
0.456 |
|
| 1995 |
Knühl G, Sennhenn P, Helmchen G. New chiral β-phosphinocarboxylic acids and their application in palladium-catalysed asymmetric allylic alkylations Journal of the Chemical Society, Chemical Communications. 1845-1846. DOI: 10.1039/C39950001845 |
0.397 |
|
| 1995 |
Urban E, Knühl G, Helmchen G. EPC synthesis of 5-substituted 2-oxo-cyclopentanecarboxylates via conjugate addition of cuprates to asymmetric shielded 2-oxo-cyclopentenecarboxylates Tetrahedron Letters. 36: 7229-7232. DOI: 10.1016/0040-4039(95)01537-R |
0.446 |
|
| 1995 |
Langer T, Illich M, Helmchen G. Diastereoselective oxidative coupling of enolates of chiral carboxylic acid derivatives Tetrahedron Letters. 36: 4409-4412. DOI: 10.1016/0040-4039(95)00786-C |
0.408 |
|
| 1995 |
Urban E, Knühl G, Helmchen G. A short synthesis of (-)-chokol A Tetrahedron. 51: 13031-13038. DOI: 10.1016/0040-4020(95)00834-U |
0.365 |
|
| 1995 |
Urban E, Knühl G, Helmchen G. Enantiomerically Pure 6-Substituted 2-Oxo-cyclohexanecarboxylates by Conjugate Addition of Cuprates to Asymmetric Shielded 2-Oxo-cyclohexenecarboxylates Tetrahedron. 51: 11149-11164. DOI: 10.1016/0040-4020(95)00676-Y |
0.435 |
|
| 1995 |
Stork T, Helmchen G. A new chiral solvating agent for carboxylic acids based on directed hydrogen bonding Recueil Des Travaux Chimiques Des Pays-Bas. 114: 253-254. DOI: 10.1002/Recl.19951140420 |
0.328 |
|
| 1994 |
Sennhenn P, Gabler B, Helmchen G. Enantiomerically pure cycloalkenylacetic acid derivatives via Pd-catalyzed asymmetric allylic alkylation and subsequent enantiomeric enrichment via iodolactones Tetrahedron Letters. 35: 8595-8598. DOI: 10.1016/S0040-4039(00)78445-0 |
0.401 |
|
| 1994 |
Sprinz J, Kiefer M, Helmchen G, Reggelin M, Huttner G, Walter O, Zsolnai L. Catalysis of allylic substitutions by Pd complexes of oxazolines containing an additional P, S, or Se Center. X-ray crystal structures and solution structures of chiral π-allyl palladium complexes of phosphinoaryloxazolines Tetrahedron Letters. 35: 1523-1526. DOI: 10.1016/S0040-4039(00)76748-7 |
0.353 |
|
| 1994 |
Berl V, Helmchen G, Preston S. Highly effective catalysts for the conjugate addition of silyl ketene acetals to enones (Mukaiyama-Michael reaction) Tetrahedron Letters. 35: 233-236. DOI: 10.1016/S0040-4039(00)76519-1 |
0.346 |
|
| 1994 |
Kiefer M, Vogel R, Helmchen G, Nuber B. Resolution of (1,1′-binaphthalene)-2,2′-dithiol by enzyme catalysed hydrolysis of a racemic diacyl derivative Tetrahedron. 50: 7109-7114. DOI: 10.1016/S0040-4020(01)85237-6 |
0.367 |
|
| 1994 |
von Matt P, Loiseleur O, Koch G, Pfaltz A, Lefeber C, Feucht T, Helmchen G. Enantioselective allylic amination with chiral (phosphino-oxazoline)pd catalysts Tetrahedron: Asymmetry. 5: 573-584. DOI: 10.1016/0957-4166(94)80021-9 |
0.428 |
|
| 1994 |
Krotz A, Helmchen G. Total Syntheses, Optical Rotations and Fragrance Properties of Sandalwood Constituents: (−)‐(Z)‐ and (−)‐(E)‐β‐Santalol and Their Enantiomers, ent‐β‐Santalene European Journal of Organic Chemistry. 1994: 601-609. DOI: 10.1002/Jlac.199419940610 |
0.363 |
|
| 1994 |
Heidel H, Huttner G, Vogel R, Helmchen G. Ein neuartiger chiraler Synthesebaustein mit Neopentangerüst: Chemo‐enzymatische Darstellung von (R)‐CH3C(CH2OSO2CF3)(CH2Cl)(CH2Br) Chemische Berichte. 127: 271-274. DOI: 10.1002/Cber.19941270138 |
0.453 |
|
| 1993 |
Kramp P, Helmchen G, Holmes AB. Syntheses of enantiomerically pure ent-multifidene and related compounds Journal of the Chemical Society, Chemical Communications. 551-552. DOI: 10.1039/C39930000551 |
0.342 |
|
| 1993 |
Sprinz J, Helmchen G. Phosphinoaryl- and phosphinoalkyloxazolines as new chiral ligands for enantioselective catalysis: Very high enantioselectivity in palladium catalyzed allylic substitutions Tetrahedron Letters. 34: 1769-1772. DOI: 10.1016/S0040-4039(00)60774-8 |
0.457 |
|
| 1993 |
Howarth J, Helmchen G, Kiefer M. Lewis acids based on sulfur containing boron heterocycles and trialkylthioboranes Tetrahedron Letters. 34: 4095-4096. DOI: 10.1016/S0040-4039(00)60624-X |
0.384 |
|
| 1993 |
Gibis KL, Helmchen G, Huttner G, Zsolnai L. Enantiomerically pure C2-symmetric bridged ferrocene and titanocene derivatives Journal of Organometallic Chemistry. 445: 181-186. DOI: 10.1016/0022-328X(93)80205-P |
0.326 |
|
| 1993 |
Helmchen G, Krotz A, Neumann H, Ziegler ML. Enantiomerically pure chiral building blocks for syntheses of carbocyclic nucleoside analogues: A formal synthesis of aristeromycin European Journal of Organic Chemistry. 1993: 1313-1317. DOI: 10.1002/Jlac.1993199301213 |
0.416 |
|
| 1992 |
Hamley P, Helmchen G, Holmes AB, Marshall DR, MacKinnon JWM, Smith DF, Ziller JW. Diastereoselective imino ester cycloadditions. Enantioselective synthesis of azabicyclo[2.2.1]heptenes Journal of the Chemical Society, Chemical Communications. 786-788. DOI: 10.1039/C39920000786 |
0.394 |
|
| 1991 |
Helmchen G, Krotz A, Ganz K, Hansen D. C
2-Symmetric Bioxazolines and Bithiazolines as New Chiral Ligands for Metal Ion Catalyzed Asymmetric Syntheses: Asymmetric Hydrosilylation Synlett. 1991: 257-259. DOI: 10.1055/S-1991-20699 |
0.349 |
|
| 1991 |
Sartor D, Saffrich J, Helmchen G, Richards CJ, Lambert H. Enantioselective Diels-Alder reactions of enals: Fighting species multiplicity of the catalyst with donor solvents Tetrahedron: Asymmetry. 2: 639-642. DOI: 10.1016/S0957-4166(00)86117-0 |
0.455 |
|
| 1990 |
Sartor D, Saffrich J, Helmchen G. Enantioselective Diels-Alder Additions with New Chiral Lewis Acids Derived from Amino Acids Synlett. 1990: 197-198. DOI: 10.1055/S-1990-21031 |
0.366 |
|
| 1990 |
Krotz A, Helmchen G. Total syntheses of sandalwood fragrances: (Z)- and (E)-β-santalol and their enantiomers, ent-β-santalene Tetrahedron: Asymmetry. 1: 537-540. DOI: 10.1016/S0957-4166(00)80544-3 |
0.393 |
|
| 1990 |
Helmchen G, Goeke A, Lauer G, Urmann M, Fries J. Building blocks for the synthesis of enantiomerically pure jasmonoids: Synthesis of (+)-methyl epijasmonate Angewandte Chemie (International Edition in English). 29: 1024-1025. DOI: 10.1002/Anie.199010241 |
0.389 |
|
| 1990 |
Helmchen G, Goeke A, Lauer G, Urmann M, Fries J. Bausteine zur Synthese von enantiomerenreinen Jasmonoiden: Synthese von (+)‐Methylepijasmonat Angewandte Chemie. 102: 1079-1081. DOI: 10.1002/Ange.19901020921 |
0.409 |
|
| 1989 |
Helmchen G, Hady AFA, Hartmann H, Karge R, Krotz A, Sartor K, Urmann M. Natural product syntheses based on asymmetric Diels-Alder reactions Pure and Applied Chemistry. 61: 409-412. DOI: 10.1351/Pac198961030409 |
0.461 |
|
| 1989 |
Linz G, Weetman J, Abdel Hady AF, Helmchen G. Asymmetric Diels-Alder reactions: EPC-synthesis of a stable sarkomycin precursor (cyclosarkomycin) Tetrahedron Letters. 30: 5599-5602. DOI: 10.1016/S0040-4039(01)93809-2 |
0.444 |
|
| 1989 |
Poll T, Abdel Hady AF, Karge R, Linz G, Weetman J, Helmchen G. N-substituted hydroxysuccinimides from (s)-malic acid as new reagents for asymmetric diels-alder additions to enoates Tetrahedron Letters. 30: 5595-5598. DOI: 10.1016/S0040-4039(01)93808-0 |
0.438 |
|
| 1987 |
Helmchen G, Ihrig K, Schindler H. EPC-syntheses via asymmetric diels-alder reactions/retro diels-alder reactions I: (R)- and (S)-matsutake alcohol. (R)- and (S)-sarcomycin methyl ester Tetrahedron Letters. 28: 183-186. DOI: 10.1016/S0040-4039(00)95681-8 |
0.387 |
|
| 1987 |
Hartmann H, Hady AFA, Sartor K, Weetman J, Helmchen G. High Stereoselectivity in Lewis‐Acid‐Catalyzed and Uncatalyzed Diels–Alder Reactions of the Fumarate of (S)‐Ethyl Lactate Angewandte Chemie. 26: 1143-1145. DOI: 10.1002/Anie.198711431 |
0.317 |
|
| 1986 |
Helmchen G. Stereoselection at 3-Carbon Units. Recent Studies and Applications in Natural Product Synthesis Cheminform. 17. DOI: 10.1002/Chin.198638359 |
0.321 |
|
| 1985 |
Poll T, Sobczak A, Hartmann H, Helmchen G. Diastereoface-discriminative metal coordination in asymmetric synthesis: D-pantolactone as practical chiral auxiliary for Lewis acid catalyzed Diels-Alder reactions Tetrahedron Letters. 26: 3095-3098. DOI: 10.1016/S0040-4039(00)98627-1 |
0.392 |
|
| 1985 |
Dorsch D, Kunz E, Helmchen G. Syntheses of dictyopterene B (hormosirene) and its enantiomer via asymmetric ScN′ reactions Tetrahedron Letters. 26: 3319-3322. DOI: 10.1016/S0040-4039(00)98287-X |
0.405 |
|
| 1985 |
Helmchen G, Wegner G. Asymmetric synthesis of β-substituted alcanoic acids via highly stereoselective conjugate additions of organocopper compounds to chiral enoates Tetrahedron Letters. 26: 6051-6054. DOI: 10.1016/S0040-4039(00)95122-0 |
0.436 |
|
| 1985 |
Helmchen G, Wegner G. Synthesis of enantiomerically pure (S)-3-trichloromethylbutyric acid via asymmetric conjugate addition of trichloromethyl metal compounds to a chiral enoate. Activation effect of a sulfonylamino group Tetrahedron Letters. 26: 6047-6050. DOI: 10.1016/S0040-4039(00)95121-9 |
0.447 |
|
| 1985 |
Poll T, Metter JO, Helmchen G. Mechanism Of The Asymmetric Diels-Alder Reaction: Initial Crystal-Structure Analysis Of A Lewis Acid Complex Of A Chiral Dienophile Cheminform. 16. DOI: 10.1002/Chin.198521070 |
0.365 |
|
| 1985 |
Roder H, Helmchen G, Peters E-, Peters K, Schnering HGV. Highly Enantioselective Homoaldol Addition With Chiral N-Allylureas - Use For The Synthesis Of Optically Pure Γ-Lactones Cheminform. 16. DOI: 10.1002/Chin.198512168 |
0.398 |
|
| 1985 |
Helmchen G, Leikauf U, Taufer‐Knöpfel I. Enantio‐ and anti‐Diastereoselective Aldol Additions of Acetates and Propionates via O‐Silyl Ketene Acetals Angewandte Chemie. 24: 874-875. DOI: 10.1002/Anie.198508741 |
0.366 |
|
| 1985 |
Poll T, Metter JO, Helmchen G. Concerning the Mechanism of the Asymmetric Diels‐Alder Reaction: First Crystal Structure Analysis of a Lewis Acid Complex of a Chiral Dienophile Angewandte Chemie. 24: 112-114. DOI: 10.1002/Anie.198501121 |
0.355 |
|
| 1984 |
Poll T, Helmchen G, Bauer B. Influence of polar groups in thermal and Lewis acid promoted asymmetric diels-alder additions: lactic acid derivatives as practical highly selective and configurationally dichotomic reagents Tetrahedron Letters. 25: 2191-2194. DOI: 10.1016/S0040-4039(01)80207-0 |
0.384 |
|
| 1984 |
Roder H, Helmchen G, Peters E, Peters K, Schnering Hv. Highly Enantioselective Homoaldol Additions with Chiral N‐Allylureas—Application to the Synthesis of Optically Pure γ‐Lactones Angewandte Chemie. 23: 898-899. DOI: 10.1002/Anie.198408981 |
0.397 |
|
| 1984 |
Helmchen G, Wierzchowski R. Preparation of Enantiomerically Pure Chiral Alcohols by Asymmetric Alkylation of Glycolates Angewandte Chemie. 23: 60-61. DOI: 10.1002/Anie.198400601 |
0.358 |
|
| 1984 |
Roder H, Helmchen G, Peters E, Peters K, Schnering Hv. Hochenantioselektive Homoaldol‐Addition mit chiralen N‐Allylharnstoffen ‐ Anwendung zur Synthese optisch reiner γ‐Lactone Angewandte Chemie. 96: 895-896. DOI: 10.1002/Ange.19840961114 |
0.415 |
|
| 1984 |
Helmchen G, Wierzchowski R. Herstellung enantiomerenreiner chiraler Alkohole durch asymmetrische Alkylierung von Glykolaten Angewandte Chemie. 96: 59-60. DOI: 10.1002/Ange.19840960116 |
0.332 |
|
| 1983 |
Helmchen G, Schmierer R. A total synthesis of enentiomerically pure vitamin e side chain using a chiral propionate synthon Tetrahedron Letters. 24: 1235-1238. DOI: 10.1016/S0040-4039(00)81623-8 |
0.399 |
|
| 1981 |
Schmierer R, Grotemeier G, Helmchen G, Selim A. Functional Groups In Concave Positions: Asymmetric Alkylation Of Esters With Very High Stereoselectivity And Configuration Inversion By Change Of Solvent Cheminform. 12. DOI: 10.1002/Chin.198124099 |
0.341 |
|
| 1981 |
Schmierer R, Grotemeier G, Helmchen G, Selim A. Functional Groups at Concave Sites: Asymmetric Alkylation of Esters with Very High Stereoselectivity and Reversal of Configuration by Change of Solvent Angewandte Chemie. 20: 207-208. DOI: 10.1002/Anie.198102071 |
0.321 |
|
| 1981 |
Helmchen G, Schmierer R. Functional Groups at Concave Sites: Asymmetric Diels‐Alder Synthesis with Almost Complete (Lewis‐Acid Catalyzed) or High (Uncatalyzed) Stereoselectivity Angewandte Chemie. 20: 205-207. DOI: 10.1002/Anie.198102051 |
0.365 |
|
| 1981 |
Helmchen G, Schmierer R. Funktionelle Gruppen in konkaver Lage: Asymmetrische Diels-Alder-Synthese mit nahezu vollständiger (Lewis-Säure-katalysiert) und hoher (unkatalysiert) Stereoselektivität†‡ Angewandte Chemie. 93: 208-209. DOI: 10.1002/Ange.19810930222 |
0.459 |
|
| 1980 |
Ade E, Helmchen G, Heiligenmann G. Synthesis of the stereoisomers of 17,21-dimethylheptatriacontane - sex recognition pheromone of the tsetse fly Tetrahedron Letters. 21: 1137-1140. DOI: 10.1016/S0040-4039(01)83933-2 |
0.448 |
|
| 1980 |
Ade E, Helmchen G, Heiligenmann G. Directed Resolution Of Enantiomers By Liquid Chromatography Of Diastereomeric Derivatives. 7. Syntheses Of The Stereoisomers Of 17,21-Dimethylheptatriacontane - Sex Recognition Pheromone Of The Tsetse Fly Cheminform. 11. DOI: 10.1002/Chin.198030342 |
0.324 |
|
| 1979 |
Glatz B, Helmchen G, Muxfeldt H, Porcher H, Prewo R, Senn J, Stezowski JJ, Stojda RJ, White DR. Tetracyclines. 10. Chemical-structural properties of tetracycline derivatives. 5. A total synthesis and structural aspects of racemic 8-oxygenated tetracyclines Journal of the American Chemical Society. 101: 2171-2181. DOI: 10.1021/Ja00502A039 |
0.65 |
|
| 1979 |
Helmchen G, Nill G, Flockerzi D, Youssef MSK. Gezielte Trennung von Enantiomeren via Flüssigkeitschromatographie diastereomerer Derivate. 5. Mitt. Gezielte präparative Trennung enantiomerer Carbonsäuren und Lactone via Flüssigkeitschromatographie und nachbargruppenunterstützte Hydrolysediastereomerer Amide. Cheminform. 10. DOI: 10.1002/Chin.197915100 |
0.341 |
|
| 1979 |
Helmchen G, Nill G, Flockerzi D, Youssef MSK. Preparative Scale Directed Resolution of Enantiomeric Carboxylic Acids and Lactones via Liquid Chromatography and Neighboring‐Group Assisted Hydrolysis of Diastereomeric Amides Angewandte Chemie. 18: 63-65. DOI: 10.1002/Anie.197900631 |
0.331 |
|
| 1979 |
Helmchen G, Nill G. Gezielte präparative Trennung enantiomerer Amine via Flüssigkeitschromatographie diastereomerer 4‐Hydroxybutyramide Angewandte Chemie. 91: 66-68. DOI: 10.1002/Ange.19790910111 |
0.473 |
|
| 1979 |
Helmchen G, Nill G, Flockerzi D, Youssef MSK. Gezielte präparative Trennung enantiomerer Carbonsäuren und Lactone via Flüssigkeitschromatographie und nachbargruppenunterstützte Hydrolyse diastereomerer Amide Angewandte Chemie. 91: 65-66. DOI: 10.1002/Ange.19790910110 |
0.452 |
|
| 1979 |
Glatz B, Helmchen G, Muxfeldt H. A total synthesis and structural aspects of racemic 8-oxygenated tetracyclines Journal of the American Chemical Society. 101: 2171-2181. |
0.622 |
|
| 1978 |
Goelz H, Glatz B, Haas G, Helmchen G, Muxfeldt H. N-Acyl-N′-Arylsulfonyldiazenes, Determination And Use In The Synthesis Of Amides Cheminform. 9. DOI: 10.1002/Chin.197802147 |
0.67 |
|
| 1977 |
Gölz H, Glatz B, Haas G, Helmchen G, Muxfeldt H. N‐Acyl‐N′‐arylsulfonyldiazenes; Detection and Use in the Synthesis of Amides Angewandte Chemie. 16: 728-729. DOI: 10.1002/Anie.197707281 |
0.657 |
|
| 1977 |
Helmchen G, Staiger G. Synthesis and Absolute Configuration of Enantiomerically Pure D3‐Trishomocubanes(Pentacyclo [6.3.0.02,6.03,10.05,9] undecane) and Trishomocubanones Angewandte Chemie. 16: 116-117. DOI: 10.1002/Anie.197701161 |
0.446 |
|
| 1977 |
Gölz H, Glatz B, Haas G, Helmchen G, Muxfeldt H. N‐Acyl‐N′‐arylsulfonyldiazene; Nachweis und Verwendung zur Synthese von Amiden Angewandte Chemie. 89: 742-743. DOI: 10.1002/Ange.19770891015 |
0.69 |
|
| 1976 |
Helmchen G, Schmierer R. Determination of the Absolute Configuration of Chiral Thiols by 1H‐NMR Spectroscopy of Diastereomeric Thiol Esters Angewandte Chemie. 15: 703-704. DOI: 10.1002/Anie.197607031 |
0.42 |
|
| 1973 |
Helmchen G, Haas G, Prelog V. Über die stereoisomeren α-Phenyläthylamide der Biphenyl-2,2′,6,6′-tetracarbonsäure, Molekeln der Punktsymmetrie D2, S4, C2 und C1 Helvetica Chimica Acta. 56: 2255-2270. DOI: 10.1002/Hlca.19730560714 |
0.59 |
|
| 1973 |
Helmchen G, Prelog V. 1,12-Dioxa-(12)Paracyclophan-Derivate Mit Einer Pseudoasymmetrieebene Cheminform. 4. DOI: 10.1002/Chin.197302304 |
0.581 |
|
| 1973 |
Helmchen G, Prelog V. Atropisomere Biphenyl-Derivate Mit Einer Pseudoasymmetrieachse Cheminform. 4. DOI: 10.1002/Chin.197302208 |
0.593 |
|
| 1973 |
Prelog V, Helmchen G. Pseudoasymmetrie In Der Organischen Chemie Cheminform. 4. DOI: 10.1002/Chin.197302060 |
0.509 |
|
| 1972 |
Helmchen G, Prelog V. Über 1, 12‐Dioxa‐[12]paracyclophan‐Derivate mit einer Pseudoasymmetrieebene Helvetica Chimica Acta. 55: 2612-2620. DOI: 10.1002/Hlca.19720550738 |
0.566 |
|
| 1972 |
Helmchen G, Prelog V. Über atropisomere Biphenyl‐Derivate mit einer Pseudoasymmetrieachse Helvetica Chimica Acta. 55: 2599-2611. DOI: 10.1002/Hlca.19720550737 |
0.61 |
|
| 1972 |
Prelog V, Helmchen G. Pseudoasymmetrie in der organischen Chemie Helvetica Chimica Acta. 55: 2581-2598. DOI: 10.1002/Hlca.19720550736 |
0.539 |
|
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