Scope of electron-deficient alkenes^a.

^aStandard reaction conditions: graphite rod anode, graphite rod cathode, constant current = 10 mA. 2 (0.3–0.4 mmol), 1a (1.5 equiv.), n-Bu₄NBF₄ (1.0 equiv.), HFIP/CH₂Cl₂ (6 : 4, 10 mL), rt, 2 h, under N₂.

^bThe reaction was conducted with a constant cell potential of +2.5 V in HFIP/CH₂Cl₂ (7 : 3, 10 mL) for 10 h at rt.