Synthesis of resveratrol

Resveratrol, (E)-3,5,4′-trihydroxystilbene, is a polyphenol found in grape skins and red wine. The E double bond between the two rings can be formed by a Julia–Kocienski olefination between the PT sulfone of 3,5-dimethoxybenzyl alcohol and 4-methoxybenzaldehyde (anisaldehyde).

With KHMDS at −78 °C resveratrol trimethyl ether is obtained with high E selectivity. The three methyl ethers are then cleaved with boron tribromide, a Lewis acid that coordinates to oxygen and facilitates attack of bromide on the methyl group.