Download PDF
Synthesis 1995; 1995(6): 687-692
DOI: 10.1055/s-1995-3978
paper
© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Simple and Efficient Stereoselective Synthesis of (Z)- and (E)-Alkylidene 2,3-Dimethoxybutenolides from L-Ascorbic Acid and D-Isoascorbic Acid

M. Akram Khan* , Harry Adams
  • *Division of Chemistry, School of Science, Sheffield Hallam University, Pond Street, Sheffield S1 1WB, England, Fax +44(114)253308; E-mail M.A.khan@shu.ac.uk
Further Information

Publication History

Publication Date:
31 December 2000 (online)

  PDF Download  Permissions and Reprints All articles of this category

Reactions of 2,3-di-O-methyl-5,6-di-O-toxyl-L-ascorbic acid (5b) and 2,3-di-O-methyl-5,6-di-O-toxyl-D-isoascorbic acid (11) with excess of carbon, oxygen and nitrogen nucleophiles produced γ-(Z)- and (E)-alkylidene-2,3-dimethoxybutenolides 6a-e and 12a-d, respectively, in good yields. The formation of the reaction products 6a-e and 12a-d has been rationalised through the involvement of two reaction processes. The ditosylates undergo a stereoselective antiperiplanar E2 reaction first with the nucleophiles to yield exocyclic allylic tosylates of the type 6 or 12 which in a subsequent SN2 reaction give rise to the observed products 6a-e and 12a-d.

alkylidine butenolides - tosylation - ascorbic acid

      >