Synthesis of fluoro-benzoxazepines via an I(iii)/BF3·Et2O-enabled 1,2-aryl migration/fluorination cascade

Abstract

A metal-free oxidative fluorination reaction of o-alkenyl aryl ureas to construct a benzoxazepine skeleton was accomplished by employing the commonly used BF₃·Et₂O as the Lewis acid/fluorine source and hypervalent iodine(III) reagent as the oxidant. The crucial step for constructing the benzoxazepine backbone lies in an exclusive 1,2-aryl migration/fluorination cascade, which is enabled by a phenyliodine(III) diacetate (PIDA)/BF₃·Et₂O reagents system.