A highly regio- and stereoselective Pd-catalyzed electrocarboxylation of Baylis-Hillman acetates: An interesting switchable regioselectivity based on electrode material

Abstract

We developed a novel regio- and stereoselective palladium catalyzed electrocarboxylation of Baylis-Hillman acetates. We found an interesting unprecedented electrode material-controlled switchable regioselectivity. When Platinum was taken as cathode, benzylic carboxylation products were found to be the predominant regioisomers (condition A). Under similar reaction conditions when Nickel was taken as cathode, a complete reversal in regioselectivity was observed providing cinnamyl carboxylation products as the predominant regio isomers with exclusively (E)-stereochemistry (condition B). We proposed plausible mechanisms to explain the switch in regioselectivity which were further supported by TEMPO experiments.