Metal-free synthesis of 2-aminobenzoxazoles using hypervalent iodine reagent

A facile, simple, mild, and metal-free protocol for the synthesis of 2-aminobenzoxazoles has been developed via C-H bond amination of benzoxazoles with amines through a ring-opening and subsequent ring-closure approach. The reaction was performed in two steps wherein nucleophilic addition of amines across benzoxazoles takes place in the absence of any reagent or catalyst under solvent-free condition, followed by oxidative ring closure using 2-iodoxybenzoic acid as a hypervalent iodine reagent. Various cyclic, acyclic, and functionalized aliphatic amines were well tolerated under optimized reaction conditions and provided good to excellent yield of respective 2-aminobenzoxazoles.