Michael-type addition of carbocuprates to acetylenic silyl ketone: a new entry to stereodefined polyenes

Ethynyl triphenylsilyl ketone (1) reacts smoothly with various carbocuprates, affording 3-functionalized propenoylsilanes. When using unsaturated carbocuprates, dienoylsilanes 2d-f are obtained. These synthetic equivalents of dienals can further react under Wittig conditions to afford a new and stereodefined entry into the class of silylated polyenes 4