Effect of noncovalent interactions in ion pairs on hypervalent iodines: inversion of regioselectivity in sulfonyloxylactonization

Abstract

We synthesized novel hypervalent iodines possessing cationic heterocyclic moieties nearby the iodine(III) center. The novel hypervalent iodines exhibited a totally different regioselectivity from common PhI(OAc)₂ during the sulfonyloxylactonization of 2-vinylbenzoic acids. The noncovalent interactions between the sulfonyloxy groups and the cationic heterocyclic moieties resulted in a significant change in the regioselectivity, which was revealed by the observation of intermediates and density functional theory studies including noncovalent interaction analysis.