Synthesis of New Sulfoximine-Tethered Alkynones and Further Extension towards Metal-Free Synthesis of Pyrimidines, Amino Pyrimidines, Pyrazoles and Isoxazoles

A metal free and divergent synthetic method has been successfully developed for the synthesis of sulfoximine tethered pyrimidines, amino pyrimidines, pyrazoles and isoxazoles. Two key sulfoximine tethered alkynone intermediates ((tert-butyl-diphenylsilyl)imino)(2-oxo-4-phenylbut-3-yn-1-yl)(phenyl)-lambda(6)-sul- fanone (3a) and ((tert-butyldiphenylsilyl)imino)(2-oxopent-3-yn1-yl)(phenyl)-lambda(6)-sulfanone (3b), have been reported for the first time and were used as the common building blocks to construct these heterocycles. Good functional group tolerability was observed and the products were isolated in excellent yield.