Table 1 Optimization Studies ^a


Entry	Variations from standard conditions	3 (%)^b
1	None	72 (68^c)
2	Without HCl	trace
3	FeCl₃ (20 mmol%) instead of HCl	trace
4	CuCl₂ (20 mmol%) instead of HCl	trace
5	C( + )/C(−) instead of C(+)/Pt(−)	61
6	Pt(+)/Pt(−) instead of C(+)/Pt(−)	46
7	I = 1.5 mA	32
8	I = 2.5 mA	26
9	DMF instead of CH₃CN	14
10	CF₃OH instead of CH₃CN	39
11	CF₃CH₂OH instead of CH₃CN	27
12	DMSO instead of CH₃CN	10
13	nBu₄NCl instead of Et₄NCl	trace
14	5.0 equiv. of cyclohexane 1	58
15	TFA/TfOH instead of HCl	N.D.
16	Without electricity	N.D.
17	Without light irradiation	N.D.

^aStandard conditions: undivided cell, graphite rod anode (φ = 3 mm), Pt plate cathode (10 × 10 × 1 mm), cyclohexane 1 (2.0 mmol, 10.0 equiv.), B₂(cat)₂ 2 (0.2 mmol, 1.0 equiv.), Et₄NCl (0.1 mmol, 0.017 M), concentrated HCl (0.8 mmol, 4.0 equiv.), CH₃CN (6.0 mL, technical grade), 390 nm LEDs (10 W), constant current = 2 mA under N₂ atmosphere at room temperature for 12 h (4.48 F/mol); then pinacol (0.6 mmol, 3.0 equiv.) and triethylamine (0.84 mL) in DCM (1.0 mL), 1 h. ^bYields determined by NMR analysis using 1,3,5-(OMe)₃C₆H₃ as the internal standard. ^cYields of isolated products. N.D. Not detected.

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