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Titolo:
Diastereoselective lithiation and substitution of (S)-N-benzylprolinol andrac-N-benzylpiperidine-2-methanol via the carbamate esters: Kinetic resolution by means of (-)-sparteine-mediated deprotonation
Autore:
Weber, B; Schwerdtfeger, J; Frohlich, R; Gohrt, A; Hoppe, D;
Indirizzi:
Univ Munster, Inst Organ Chem, D-48149 Munster, Germany Univ Munster Munster Germany D-48149 rgan Chem, D-48149 Munster, Germany Bayer AG, D-51368 Leverkusen, Germany Bayer AG Leverkusen Germany D-51368 ayer AG, D-51368 Leverkusen, Germany
Titolo Testata:
SYNTHESIS-STUTTGART
fascicolo: 11, , anno: 1999,
pagine: 1915 - 1924
SICI:
0039-7881(199911):11<1915:DLASO(>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
BETA-AMINO ALCOHOLS; ENANTIOSELECTIVE SYNTHESIS; ORGANIC-SYNTHESIS; LITHIUM AMIDE; STEREOSELECTIVE GENERATION; ASYMMETRIC DEPROTONATION; C-SUBSTITUTION; COMPLEX; ACIDS; AGGREGATION;
Keywords:
beta-amino alcohols; beta-amino-alpha-oxy carbanions; diastereoselective deprotonation; (-)-sparteine; kinetic resolution; carbanions; lithiation; Mosher esters;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Hoppe, D Univ Munster, Inst Organ Chem, Corrensstr 40, D-48149 Munster, Germany Univ Munster Corrensstr 40 Munster Germany D-48149 ster, Germany
Citazione:
B. Weber et al., "Diastereoselective lithiation and substitution of (S)-N-benzylprolinol andrac-N-benzylpiperidine-2-methanol via the carbamate esters: Kinetic resolution by means of (-)-sparteine-mediated deprotonation", SYNTHESIS-S, (11), 1999, pp. 1915-1924

Abstract

The (S)-N-benzylprolinol carbamate (S)-8 is deprotonated by sec-butyllithium with the removal of the pro-R-H and the intermediate lithium compound 10is trapped by several electrophiles. Complete ul-diastereotopos-differentation is achieved irrespective of the supporting additive [TMEDA, (-)-sparteine, or ether]. For the homologous piperidine derivative rac-9, the substrate-directed diastereoselectivity is less pronounced (similar to 6:1). Thus,an efficient kinetic resolution is observed by means of sec-butyllithium/(-)sparteine, leading to the preferential consumption of the (+)-(R)-9 with abstraction of the pro-S-H, followed by its substitution by electrophiles. Enantioenriched (-)-(S)-9 remains unchanged.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 21:10:18