Isothiourea-Catalyzed Atroposelective N-Acylation of Sulfonamides.

We report herein an atroposelective N-acylation of sulfonamides using a commercially available isothiourea catalyst, (S)-HBTM, with a simple procedure. The N-sulfonyl anilide products can be obtained in good to high enantiopurity, which represents a new axially chiral scaffold. The application of the product as a chiral iodine catalyst is also demonstrated for the asymmetric α-oxytosylation of propiophenone.