Efficient preparation of trisubstituted alkenes using the SmI2 modification of the Julia-Lythgoe olefination of ketones and aldehydes

High yields of di- and tri-substituted alkenes are: obtained by a modification of the Julia-Lythgoe olefination reaction involving the in situ capture of intermediate beta -alkoxy-sulfones by benzoyl or trimethylsilyl chloride, followed by SmI2-mediated reductive elimination. This novel protocol also provides a connective preparation of dienyl ethers, which are important partners in Diels-Alder cycloadditions. (C) 2001 Elsevier Science Ltd. All rights reserved.