Table 1. Optimization of Ni-NIXANTPHOS catalyzed DCCP of 1a with 2a ^a .

Entry	1a : 2a : base	Ni/L (mol%)	T (°C)	t (h)	Concn	Yield b (%)
1	1.2 : 1 : 3	10/10	110	16	0.1	78
2	1.2 : 1 : 3	10/15	110	16	0.1	71
3	1.2 : 1 : 3	10/20	110	16	0.1	62
4	1.2 : 1 : 2	10/10	110	16	0.1	83
5	1.2 : 1 : 2	10/10	110	16	0.05	85
6	1 : 1.5 : 2	10/10	110	16	0.05	93
7	1 : 1.5 : 2	10/10	110	8	0.05	77
8	1 : 1.5 : 2	10/10	110	24	0.05	81
9	1 : 1.5 : 2	10/10	50	16	0.05	99
10	1 : 1.5 : 2	10/10	rt	16	0.05	99
11 c	1 : 1.5 : 2	2.5/2.5	rt	16	0.05	99(99)
12	1 : 1.5 : 2	1/1	rt	16	0.05	72

^aReactions conducted on a 0.10 mmol scale.

^bYield determined by ¹H NMR spectroscopy of the crude reaction mixtures.

^cIsolated yield after chromatographic purification.