The polar effect on the regiochemistry of nucleophilic substitution of trifluoromethylated π-allylpalladium complex

Allylic nucleophilic substitution of trifluoromethyl-group substituted cinnamyl carbonate with diethyl malonate anion in the presence of palladium complex catalyst gave regio- and stereoselectively the SN2′ product. The regiochemistry caused by the polar effect of trifluoromethyl group was opposite to the methylated cinnamyl substrate in a similar steric environment. The sterically more hindered mesityl and tert-butyl substrates than phenyl derivative also gave the products reacted at the more hindered sites. Although o-substituted substrates expecting intramolecular coordination to affect regiochemistry were examined, no alternative regioisomers were detected.