Table 1 Screening of reaction conditions.^a


Entry	Variation from standard conditions	Yield of 2 (%)	Recovery of 1 (%)
1	None	92	6
2	w/o Ph₃SiCl	trace	81
3	Al(+)/Ni Foam(−)	12	73
4	Zn(+)/Ni Foam(−)	0	95
5	Mg(+)/Ni Foam(−)	0	93
6	Fe or GF as cathode	90/75	5/10
7	TMSCl or TMSBr instead of Ph₃SiCl	89/86	0/0
8	(TMS)₂O instead of Ph₃SiCl	90	trace
9	Ph₃SiH instead of Ph₃SiCl	73	14
10	DMA, NMP or CH₃CN as solvent	10/20/0	87/30/90
11	MeOH or EtOH instead of H₂O	93/91	0/0
12	with CoBr₂^.dtbpy (5 mol%)	94	0
13	with NiBr₂^.dtbpy (5 mol%)	95	0
14^b	with NiBr₂^.dtbpy (5 mol%)	99(98)^c	0
15	no electricity	0	>99

Bold formatting shows that entry 14 is the optimal reaction condition.
dtbpy 4,4′-di-tert-butyl-2,2′-bipyridine, TBABF₄ ⁿBu₄NBF₄, RT room temperature, GF graphite felt, TMSCl chlorotrimethylsilane, TMSBr bromotrimethylsilane, (TMS)₂O hexamethyldisiloxane, DMF N, N-dimethylformamide, DMA N, N-Dimethylacetamide, NMP N-methyl-2-pyrrolidone.
^a Reaction conditions: undivided cell, Fe as the anode, Ni foam as the cathode, constant current = 6 mA, 1 (0.3 mmol, 1.0 equiv.), Ph₃SiCl (20 mol%), H₂O (3.0 equiv.), TBABF₄ (1.0 equiv.) in DMF (4.0 mL), room temperature, 10 h, under Ar atmosphere. Yields were determined by ¹H NMR spectroscopy using 1,3,5-trimethoxybenzene as the internal standard.
^bConstant current = 5 mA.
^cIsolated yield.

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