Efficient synthesis of protected sulfonopeptides from N-protected 2-aminoalkyl xanthates and thioacetates

An efficient and convenient method was developed for the synthesis of protected sulfonopeptides via N-chlorosuccimide (NCS)/HCl oxidative chlorination of N-protected 2-aminoalkyl xanthates or thioacetates to the corresponding sulfonyl chlorides followed by aminolysis with amino esters. In the current method, sulfonopeptides containing 1- and 2-substituted taurines were prepared in satisfactory to good yields. It is a useful and efficient strategy for the synthesis of protected sulfonopeptides with functionalized side-chains.