Abstract A new approach for the diastereoselective synthesis of (±)-α-noscapine, a phthalide tetrahydroisoquinoline alkaloid exhibiting several biological activities, is described. The strategy features a blocking group-directed Bischler–Napieralski reaction followed by diastereoselective reduction (α/β> 23: 1). One of the key intermediates, phthalide-3- carboxylic acid, could be efficiently prepared from simple benzoic acid derivative and ...
