STEREOCHEMISTRY OF THE FORMATION OF ENDOCYCLIC SULFOXIMIDES FROM O-CARBOXYPHENYL SULFOXIDES

The stereochemistry of the amination and subsequent cyclodehydration o f optically active 2-(octylsulfinyl)benzoic acid to yield the correspo nding endocyclic sulfoximide (1-octyl-3-oxo-benzo[d]-isothia(IV)azole 1-oxide) was studied using two different amination reagents, viz. hydr azoic acid and O-(mesitylenesulfonyl)hydroxylamine (MSH), respectively . It was found that while the reaction with hydrazoic acid yielded a p artially racemized product having the same sign of optical rotation as the sulfoxide precursor, MSH gave essentially complete formation (>94 %) of enantiopure product with the opposite sign of rotation. This dif ference in stereochemistry is likely to be caused by a neighbouring ca rboxyl group participation taking place in the strong acid medium used in the first case.