Construction of Trifluoromethyl‐Bearing Quaternary Carbon Centers by Intramolecular Decarboxylative Allylation of α‐Trifluoromethyl β‐Keto Esters

A new palladium-catalyzed decarboxylative allylation of allyl α-trifluoromethyl-β-keto esters was developed in the presence of tris(dibenzylideneacetone)dipalladium [Pd2(dba)3] and 1,2-bis(diphenylphosphino)ethane (dppe) in tetrahydrofuran. α-Trifluoromethyl ketones featuring a quaternary carbon center were produced in good yields and the dreaded α,β-unsaturated-β,β-difluoro ketones resulting from β-elimination of a fluoride ion was not observed.