5- exo -Selective asymmetric bromolactonization of stilbenecarboxylic acids catalyzed by phenol-bearing chiral thiourea.

We developed a novel thiourea Lewis-base catalyst with phenol moieties for the enantioselective 5- exo -bromolactonization of stilbenecarboxylic acids to afford chiral 3-substituted phthalides. The phenol moieties are crucial for the enantio- and regio-selectivity.