Asymmetric esterification of ketenes catalyzed by an N-heterocyclic carbene

The chiral N-heterocyclic carbene precursor 2, derived from L-pyroglutamic acid, was found to be an efficient precatalyst for the enantioselective esterification of alkylarylketenes with benzhydrol to give the corresponding esters in good yields with good to high enantioselectivities (up to 95% ee).