Synthesis 2005(20): 3613-3619  
DOI: 10.1055/s-2005-918498
PAPER
© Georg Thieme Verlag Stuttgart · New York

Sequential Cyclosulfonylation and Alkylation as a Versatile Strategy for Dihydropyran Synthesis

Gavin L. Edwards*, David J. Sinclair
School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia
Fax: +61(2)93856141; e-Mail: g.edwards@unsw.edu.au;
Further Information

Publication History

Received 26 October 2005
Publication Date:
24 November 2005 (online)

Abstract

Deprotonation of 3,4-dihydro-6-(p-toluenesulfonyl­methyl)-2H-pyran (2) with n-BuLi and alkylation of the lithiated ally­l sulfone gives good to excellent yields of monoalkylated products 3. No γ-substitution is observed in the monoalkylated products. A second deprotonation allows for the introduction of a second alkyl group. Desulfonylation can be effected with either sodium amalgam or sodium/ethanol in THF.