UEBER EINE NEUE METHODE ZUR BESTIMMUNG DER ABSOLUTEN KONFIGURATION VON CHIRALEN SEKUNDAEREN ALKOHOLEN UND AMINEN: NMR-SPEKTROSKOPIE VON DIASTEREOMEREN ESTERN UND AMIDEN DER ALPHA -PHENYLBUTTER- UND HYDRATROPASAEURE. = SUR UNE NOUVELLE METHODE D'ETUDE DE LA CONFIGURATION ABSOLUE D'ALCOOLS ET D'AMINES SECONDAIRES CHIRAUX: LA SPECTROSCOPIE DE RMN DE DIASTEREOISOMERES D'ESTERS ET AMIDES DES ACIDES ALPHA -PHENYLBUTYRIQUE ET HYDRATROPIQUEHELMCHEN G.1974; TETRAHEDRON LETTERS; G.B.; DA. 1974; NO 16; PP. 1527-1530; BIBL. 11 REF.Article

BESTIMMUNG DER ABSOLUTEN KONFIGURATION VON CHIRALEN THIOLEN DURCH ¹H-NMR-SPEKTROSKOPIE DIASTEREOMERER THIOLESTER. = DETERMINATION DE LA CONFIGURATION ABSOLUE DE THIOLS CHIRAUX PAR SPECTROSCOPIE DE RMN PROTONIQUE DE THIOESTERS DIASTEREOISOMERESHELMCHEN G; SCHMIEDER R.1976; ANGEW. CHEM.; DTSCH.; DA. 1976; VOL. 88; NO 22; PP. 770-771; BIBL. 4 REF.Article

A TOTAL SYNTHESIS OF ENANTIOMERICALLY PURE VITAMIN E SIDE CHAIN USING A CHIRAL PROPIONATE SYNTHONHELMCHEN G; SCHMIERER R.1983; TETRAHEDRON LETTERS; ISSN 0040-4039; GBR; DA. 1983; VOL. 24; NO 12; PP. 1235-1238; BIBL. 14 REF.Article

UBER 1,12-DIOXA-(12) PARACYCLOPHAN-DERIVATE MIT EINER PSEUDOASYMMETRIEEBENE = SUR LES DERIVES DU DIOXA-1,12 (12) PARACYCLOPHANE AVEC UN PLAN DE PSEUDO-ASYMETRIEHELMCHEN G; PRELOG V.1972; HELV. CHIM. ACTA; SUISSE; DA. 1972; VOL. 55; NO 7; PP. 2612-2620; ABS. ANGL.; BIBL. 15 REF.Serial Issue

SYNTHESE UND ABSOLUTE KONFIGURATION DER ENANTIOMER REINEN D₃-TRISHOMOCUBANE (PENTACYCLO (6.3.0.0^2,6.0^3,10.0^5,9) UNDECANE) UND TRISHOMOCUBANONE. = SYNTHESE ET CONFIGURATION ABSOLUE DU D₃-TRISHOMOCUBANE (PENTACYCLO (6.3.0.0^2,6.0^3,10.0^5,9) UNDECANE) A L'ETAT D'ENANTIOMERES PURS ET DE LA TRISHOMOCUBANONEHELMCHEN G; STAIGER G.1977; ANGEW. CHEM.; DTSCH.; DA. 1977; VOL. 89; NO 2; PP. 119-120; BIBL. 6 REF.Article

DETERMINATION OF OPTICAL PURITY BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHYHELMCHEN G; STRUBERT W.1974; CHROMATOGRAPHIA; ALLEM.; DA. 1974; VOL. 7; NO 12; PP. 713-715; BIBL. 10 REF.Article

SYNTHESES OF THE STEREOISOMERS OF 17,21-DIMETHYLHEPTATRIACONTANE-SEX RECOGNITION PHEROMONE OF THE TSETSE FLY^1,2ADE E; HELMCHEN G; HEILIGENMANN G et al.1980; TETRAHEDRON LETTERS; GBR; DA. 1980; VOL. 21; NO 12; PP. 1137-1140; BIBL. 15 REF.Article

DIRECTED RESOLUTION OF ENANTIOMERS VIA LIQUID CHROMATOGRAPHY OF DIASTEREOMERIC DERIVATIVES. III. A CONVENIENT METHOD TO DETERMINE THE ABSOLUTE CONFIGURATION OF CARBOXYLIC ACIDS R¹R²HCCOOH.HELMCHEN G; VOLTER H; SCHUHLE W et al.1977; TETRAHEDRON LETTERS; G.B.; DA. 1977; NO 16; PP. 1417-1420; BIBL. 16 REF.Article

TRANSTHIOACETALISIERUNG. EINE EINFACHE METHODE ZUR HYDROLYTISCHEN SPALTUNG VON THIOACETALEN. = TRANSTHIOACETALISATION. UNE METHODE SIMPLE POUR LA COUPURE HYDROLYTIQUE DE THIOACETALSMUXFELDT H; UNTERWEGER WD; HELMCHEN G et al.1976; SYNTHESIS; GERM.; DA. 1976; NO 10; PP. 694-696; BIBL. 16 REF.Article

Asymmetric synthesis of β-substituted alcanoic acids via highly stereoselective conjugate additions of organocopper compounds to chiral enoatesHELMCHEN, G; WEGNER, G.Tetrahedron letters. 1985, Vol 26, Num 49, pp 6051-6054, issn 0040-4039Article

Herstellung enantiomerenreiner chiraler Alkohole durch asymmetrische Alkylierung von Glykolaten = Préparation d'alcools chiraux optiquement purs par alkylation asymétrique de glycolates = Synthesis of optically pure chiral alcohols by asymetric alkylation of glycolatesHELMCHEN, G; WIERZCHOWSKI, R.Angewandte Chemie. 1984, Vol 96, Num 1, pp 59-60, issn 0044-8249Article

FUNKTIONELLE GRUPPEN INKONKAVER LAGE: ASYMMETRISCHE ALKYLIERUNG VON ESTERN MIT SEHR HOHER STEREOSELEKTIVITAET UND KONFIGURATIONSUMKEHRUNG DURCH SOLVENSAENDERUNG = GROUPES FONCTIONNELS EN POSITION CONCAVE: ALKYLATION ASYMETRIQUE D'ESTERS AVEC UNE TRES GRANDE STEREOSELECTIVITE ET INVERSION DE CONFIGURATION PAR CHANGEMENT DE SOLVANTSCHMIERER R; GROTEMEIER G; HELMCHEN G et al.1981; ANGEW. CHEM.; ISSN 0044-8249; DEU; DA. 1981; VOL. 93; NO 2; PP. 209-211; BIBL. 13 REF.Article

N-ACYL-N'-ARYLSULFONYLDIAZENE; NACHWEIS UND VERWENDUNG ZUR SYNTHESE VON AMIDEN. = N-ACYL N'-ARENSULFONYL DIAZENE; CARACTERISATION ET UTILISATION POUR LA SYNTHESE D'AMIDESGOLZ H; GLATZ B; HAAS G et al.1977; ANGEW-CHEM.; DTSCH.; DA. 1977; VOL. 89; NO 10; PP. 742-743; BIBL. 3 REF.Article

Phosphinoaryl- and phosphinoakyloxazolines as new chiral ligands for enantioselective catalysis : very high enantioselectivity in palladium catalyzed allylic subsitutionsSPRINZ, J; HELMCHEN, G.Tetrahedron letters. 1993, Vol 34, Num 11, pp 1769-1772, issn 0040-4039Article

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 groupHELMCHEN, G; WEGNER, G.Tetrahedron letters. 1985, Vol 26, Num 49, pp 6047-6050, issn 0040-4039Article

A TOTAL SYNTHESIS AND STRUCTURAL ASPECTS OF RACEMIC 8-OXYGENATED TETRACYCLINESGLATZ B; HELMCHEN G; MUXFELDT H et al.1979; J. AMER. CHEM. SOC.; USA; DA. 1979; VOL. 101; NO 8; PP. 2171-2181; BIBL. 60 REF.Article

EPC-syntheses via asymmetric Diels-Alder reactions/retro Diels-Alder reactions. I: (R)- and (S)-Matsutake alcool, (R)- and (S)-sarcomycin methyl esterHELMCHEN, G; IHRIG, K; SCHINDLER, H et al.Tetrahedron letters. 1987, Vol 28, Num 2, pp 183-186, issn 0040-4039Article

Syntheses of dictyopterene B (Hormosirene) and its enantiomer via asymmetric S_cN' reactions^1aDORSCH, D; KUNZ, E; HELMCHEN, G et al.Tetrahedron letters. 1985, Vol 26, Num 28, pp 3319-3322, issn 0040-4039Article

Ein neuartiger chiraler Synthesebaustein mit Neopentangerüst : Chemo-enzymatische Darstellung von (R)-CH₃C(CH₂OSO₂CF₃)(CH₂Cl)(CH₂Br) = A novel chiral building block with neopentane framework for synthesis: chemo-enzymatic preparation of (R)-CH₃C(CH₂OSO₂CF₃)(CH₂Cl)(CH₂Br)HEIDEL, H; HUTTNER, G; VOGEL, R et al.Chemische Berichte. 1994, Vol 127, Num 1, pp 271-274, issn 0009-2940Article

Highly effective catalysts for the conjugate addition of silyl ketene acetals to enones (Mukaiyama-Michael reaction)BERL, V; HELMCHEN, G; PRESTON, S et al.Tetrahedron letters. 1994, Vol 35, Num 2, issn 0040-4039, 189, 233-236 [5 p.]Article

Syntheses of enantiomerically pure ent-multifidene and related compoundsKRAMP, P; HELMCHEN, G; HOLMES, A. B et al.Journal of the Chemical Society. Chemical communications. 1993, Num 6, pp 551-552, issn 0022-4936Article

Zum Mechanismus der asymmetrischen Diels-Alder-Reaktion: Erste Kristallstrukturanalyse eines Lewis-Säure-Komplexes eines chiralen Dienophils = Mécanisme de la réaction asymétrique de Diels-Alder: première analyse de la structure cristalline d'un complexe acide de Lewis d'un diénophile chiral = Concerning the mechanism of the asymmetric Diels-Alder reaction: first crystal structure analysis of a Lewis acid complex of a chiral dienophilePOLL, T; METTER, J. O; HELMCHEN, G et al.Angewandte Chemie. 1985, Vol 97, Num 2, pp 116-118, issn 0044-8249Article

Resolution of(1,1'-binaphthalene)-2,2'-dithiol by enzyme catalysed hydrolysis of a racemic diacyl derivativeKIEFER, M; VOGEL, R; HELMCHEN, G et al.Tetrahedron (Oxford. Print). 1994, Vol 50, Num 24, issn 0040-4020, VI, 7109-7114 [7 p.]Article

Enantio- und anti-diastereoselektive Aldoladditionen von Acetaten und Propionaten über O-Silylketenacetale = Enantio- et anti-diastéréosélective addition aldolique d'acétates et de propionates par l'intermédiaire de O-silyl acétals de cétène = Enantio- and anti- diastereoselective aldol additions of acetates and propionates via O-silyl cetene acetalsHELMCHEN, G; LEIKAUF, U; TAUFER-KNÖPFEL, I et al.Angewandte Chemie. 1985, Vol 97, Num 10, pp 874-876, issn 0044-8249Article

Diastereoface-discriminative metal coordination in asymmetric synthesis: D-pantolactone as practical chiral auxiliary for Lewis acid catalyzed Diels-Alder reactionsPOLL, T; SOBCZAK, A; HARTMANN, H et al.Tetrahedron letters. 1985, Vol 26, Num 26, pp 3095-3098, issn 0040-4039Article