Diastereoselective Synthesis of Vinylcyclopropanes from Dienes and Sulfur Ylides

The reaction of aryl- and vinyl-stabilized sulfonium ylides with electron-poor dienes has been investigated. Clean cyclopropanation to 2-aryl- and 2-vinyl-substituted vinylcyclopropanes, with high regio- and stereocontrol, was observed. This new diastereoselective strategy was applied to formal synthesis of lamoxirene and dictyopterene B.