Table 1.

Optimization of the reaction conditions

Entry	Ni/NHC	Additive	Solvent	Time, h	T, oC	Yield of 11d, (%)
1	7a	HCO2Na	dioxane	16	110	trace
2	7b	HCO2Na	dioxane	16	110	trace
3	7с	HCO2Na	dioxane	16	110	trace
4	7d	HCO2Na	dioxane	16	110	95
5	7e	HCO2Na	dioxane	16	110	37
6	7f	HCO2Na	dioxane	16	110	91
7	7a	tBuONa	o-xylene	1	150	51
8	7a	tBuONa	o-xylene	20	150	trace
9	7b	–	o-xylene	16	150	61
10	7d	HCO2Na	o-xylene	16	110	81
11	7d	HCO2Na	toluene	16	110	86
12	7d	HCO2Na	DMF	16	110	0
13	7d	HCO2Na	NMP	16	110	0
14	7d	HCO2Na	dioxane	16	120	94
15	7d	HCO2Na	dioxane	16	100	64
16	7d	HCO2Na	dioxane	24	110	98 (91)[a]
17	7f	–	dioxane	16	110	89
18	NiCp2[b] + IMes·HCl[b]	HCO2Na	dioxane	24	110	85

^[a] Isolated yield.

^[b] 10 mol%.