Expeditious diastereoselective construction of a thiochroman skeleton via a
cinchona alkaloid-derived catalyst
An example of diastereoselective and enantioselective synthesis of thiochroman derivatives through a sulfa-Michael–Michael cascade sequence is disclosed. This is a significant complement of the quinine-thiourea catalyzed sulfa-Michael–Michael cascade reaction. The densely functionalized target thiochromans were obtained in high diastereoselectivities, and with high to excellent enantioselectivities.