PAPER	Synthesis 2007: 1209-1213   DOI: 10.1055/s-2007-965972
© Georg Thieme Verlag Stuttgart · New York
Synthesis of Substituted Tetrahydropyrans via Intermolecular Reactions of δ-Halocarbanions with Aldehydes
Michał Barbasiewicz, Aneta Brud, Mieczysław Mąkosza*
Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, P. O. Box 58, 01-224 Warsaw 42, Poland Fax: +48(22)6326681; e-Mail: icho-s@icho.edu.pl;
Received 4 January 2007

Abstract

Intramolecular substitution in δ-halocarbanions leading to cyclobutanes is a relatively slow process, thus they readily add to carbonyl groups; the thus-produced anionic adducts cyclize to tetrahydropyran derivatives. A simple mechanistic discussion, optimization of the reaction conditions, and scope of the reaction is presented.

Key words

aldol reactions - sulfones - halocarbanions - cyclizations - tetrahydropyrans