HETEROCYCLES

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact: purchase@heterocycles.com

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

■ The Role of Lone Pair Interactions in the Selective Functionalisation of Some 4,6-O-Benzylidene-hexopyranosides by Both the Phase Transfer Esterification Reactions and the Tin-mediated Esterification and Alkylation Reactions

Vernon G. S. Box

*Department of Chemistry, Mona Campus, University of the West Indies, Mona, Kingston 7, Jamaica

Abstract

The esterifications of some 4,6-O-benzylidene-hexo-pyranosides by the phase transfer method are reviewed and a mechanism for these reactions is proposed which takes into account the differential nucleophilicities of the oxygens, O-2 and O-3, as predicted by the β-effect and the γ-effect. The similarities between the tin mediated esterification and alkylation reactions of these monosaccharides and the corresponding phase transfer reactions lead to the proposal of a mechanism for the path of the tin mediated processes. The alkylation of diols by diazoalkanes in the presence of catalytic amounts of tin salts is reviewed and a mechanism is proposed for these reactions, which rationalises the apparently inverse reactivity of the ‘hydroxyl groups’.