Table 3. Optimization of Pd–NiXantphos Catalyzed DCCP of 1a with 2a^a.

entry	1a:2a	Pd (mol %)	solvent	concentration (M)	yield (%)b
1	1.2:1.0	10	CPME	0.1	87
2	1.2:1.0	10	DME	0.1	61
3	1.2:1.0	10	2-MeTHF	0.1	78
4	1.2:1.0	10	THF	0.1	>95
S	1.2:1.0	10	dioxane	0.1	25
6	1.2:1.0	10	MTBE	0.1	10
7	1.2:1.0	5	THF	0.1	79
8	1.2:1.0	5	THF	0.2	58
9c	1.2:1.0	5	THF	0.2	76
10	1.0:2.0	5	THF	0.2	>95 (99)d
11	1.0:2.0	2.5	THF	0.2	(81)d

^aReactions conducted on a 0.1 mmol scale using 1a, 2a, and 3 equiv of KN(SiMe₃)₂ at 24 °C.

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

^c5 mol % the methanesulfonate precatalyst 4 was used in place of Pd(OAc)₂/NiXantphos.

^dIsolated yield after chromatographic purification.