Transient bromoiodane mediated bromocyclization of 2- alkynylaryloate esters

Abstract

Isocoumarin is a class of O-containing heterocycles with a broad spectrum of applications in pharmacological, agrochemical, and material sciences. Introducing a halogen atom at the 4-position of isocoumarin provides a handle for further derivatization. We show an easy method to synthesize 4- bromoisocoumarin under very mild conditions, using a bench stable hypervalent iodine reagent and simply available alkali metal bromide. Our one-pot, one-step reaction follows a 6-endo-dig-cyclization strategy for making new bonds. The generality and mechanistic insight of the reaction are addressed here, followed by post-synthetic modifications. Also, a catalytic pathway has been uncovered side by side.