Development of a Large-Scale Asymmetric Process for tert-Butanesulfinamide

Process development for a scalable and green synthesis of chiral tert-butanesulfinamide (TBSA) on a multikilogram scale is reported. The process is based on the identification of a chiral sulfinyl transfer agent, benzo­[1,3]­oxathiozin-2-one, that contains active and differentiated S–N and S–O bonds, allowing the synthesis to proceed under mild reaction conditions. This method is practical and overcomes the disadvantages of earlier methods deploying harsh reaction conditions and hazardous and toxic reagents.