Trimethylsilyl crotonate is a reactive silyl ester used in organic synthesis as an α,β-unsaturated acyl donor. It facilitates stereoselective carbon-carbon bond formations in reactions such as Mukaiyama aldol additions and conjugate (Michael) additions. The compound's mild reactivity and compatibility with various catalysts make it essential for assembling complex molecules in pharmaceutical, agrochemical, and natural product synthesis. It enables efficient transfer of the crotonoyl group under aprotic conditions, often avoiding harsh reagents.