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Herstellung von Hilfsstoffen für die asymmetrische Synthese aus Weinsäure. Addition von Butyllithium an Aldehyde in chiralem Medium
Author(s) -
Seebach Dieter,
Kalinowski HansOtto,
Bastani Bahram,
Crass Gerhard,
Daum Hermann,
Dörr Hennig,
Dupreez Nicolaas P.,
Ehrig Volker,
Langer Werner,
Nüssler Christa,
Oei HocAn,
Schmidt Manfred
Publication year - 1977
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19770600202
Subject(s) - chemistry , tartaric acid , butyllithium , organic chemistry , butane , malic acid , succinic acid , medicinal chemistry , catalysis , citric acid
Preparation of Auxiliaries for Asymmetric Syntheses from Tartaric Acid. Additions of Butyllithium to Aldehydes in Chiral Media. Chiral derivatives of the complexing 1,2‐diheterosubstituted ethanes A–D are prepared from tartaric acid. The key starting materials are the succinic acid derivative 1 , the dioxolane 2a , and the diamide 3a . These are converted to the ethers, alkoxyamines, and alkylthio‐amines listed in the first column of Table 2 which also contains the derivatives 21c, 22d , and 23d made from lactic acid, malic acid, and proline, respectively. It is shown that the highest optical yields (up to 40%) in reactions of butyllithium with aldehydes are obtained when mixtures of (−)‐1,2,3,4‐tetramethoxy‐butane ( 4b ), (+)‐2,3‐dimethoxy‐ N , N , N ′, N ′‐tetramethyl‐1,4‐butanediamine ( 17a ), and (−)‐1,4‐dimethoxy‐ N , N , N ′, N ′‐tetramethyl‐2,3‐butanediamine ( 14c ) with pentane are used at temperatures down to −150° and ratios of auxiliary/butyllithium of up to 10:1 (see equation (1), Tables 2–4).