Dearomatizing spirocyclization of thioureas, ureas and guanidines

Abstract

An investigation of the dearomatization reactions of benzylic thioureas, ureas and guanidines using hypervalent iodine reagents is described. Initial attempts to perform this reaction with methyl aryl ethers was compromised by electrophilic addition leading to the formation of benzo[d]thiazoles. However, inverting the direction of the process and oxidizing the corresponding phenol delivered the desired spiro fused heterocycles in moderate to good yields for all three families.