Palladium-catalyzed regiocontrolled and stereoselective alkylations of bis(trifluoroethyl) malonates with dienyl alcohols

The triethylborane-promoted and palladium-catalyzed reactions of 2,4-dienyl alcohols or the corresponding isomeric divinyl alcohols with bis(trifluoroethyl) malonates provide an improved method for the regio- and stereoselective dienylation of malonates. The phosphine ligand is an important control element in the reaction. Combinations of Pd(OAc)2 with BIPHEP or BINAP give dienylated malonates in good yield and higher isomeric purity than the traditional combination of Pd(OAc)2 and Ph3P affords in the catalyzed reactions of dienyl acetates.