Carbeneinsertion into the C(sp2)−H bonds of internal alkenes was enabled in air by HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) as both the mediator and solvent through its cooperation with borane B(C6F5)3 as the catalyst. 3-Diazooxindoles and 3-diazoindolin-2-imines were amenable to work as the carbene precursors, and α-oxo ketene dithioacetals acted as the internal alkenes at ambient temperature. The