Herein, a method to access 3-trifluoromethyl-1,4-benzoxazines from CF3-imidoyl sulfoxonium ylides and 2-bromophenols has been demonstrated. This synthetic protocol proceeds via a one-pot two-step sequence that includes the lithium-bromide-promoted O-H insertion of sulfoxonium ylides and annulation, and has the merits of broad substrate scope, excellent functional tolerance and operational simplicity, which provides an alternative means of obtaining CF3-substituted heterocycles.