Rhodium-Catalyzed Asymmetric Trifluoromethoxylation of Racemic Allylic Trichloroacetimidates

A rhodium/diene catalyzed asymmetric allylic trifluoromethoxylation reaction is reported, which afforded chiral trifluoromethoxylated allylic compounds in 52%-97% yields with up to 97% enantiomeric excess. These are the first examples of asymmetric allylic trifluoromethoxylation. The reactions proceed via a dynamic kinetic process that allowed for the use of racemic allylic trichloroacetimidates as substrates. Density functional theory calculations showed that the formation of the C-OCF3 bond occurs via outer -sphere nucleophilic attack. Importantly, the presence of the allylic group in the products enabled them to be converted into a diverse array of optically active trifluoromethylated molecules that are otherwise difficult to access.