Highly diastereoselective 1,4-addition of an organocuprate to methyl α-D-gluco-, α-D-manno-, or α-D-galactopyranosides tethering an α,β-unsaturated ester. Novel asymmetric access to β-C-substituted butanoic acids

K. Totani, T. Nagatsuka, S. Yamaguchi, K. I. Takao, S. Ohba, K. I. Tadano

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The 1,4-addition of magnesium divinylcuprate prepared from vinylmagnesium bromide and cuprous bromide to some 4-O-crotonyl derivatives of methyl α-D-glucopyranoside proceeds with a high level of diastereochemical induction, providing the adduct in good-to-excellent yields. Other organocuprates also serve as effective carbon nucleophiles for the 1,4-addition. Removal of the carbohydrate moiety from each adduct afforded a variety of β-C-substituted butanoic esters in remarkable enantiomeric excess. The 1,4-addition of the same cuprate to some methyl α-D-manno- or α-D-galactopyranosidic substrates in which a crotonyl group was incorporated, each at 3-OH, was also investigated. The reverse π-facial attack of the cuprate was observed when some D-manno-type substrates were subjected to 1,4-addition conditions similar to those used for the D-gluco-type substrates. Furthermore, some D-galacto-type substrates provided 1,4-adducts with higher diastereoselectivities.

Original languageEnglish
Pages (from-to)5965-5975
Number of pages11
JournalJournal of Organic Chemistry
Volume66
Issue number18
DOIs
Publication statusPublished - 2001 Sep 7

ASJC Scopus subject areas

  • Organic Chemistry

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