Table 3.

Reactions of methyl 4-phenyl-4-oxobutanoate with tert-butyl acrylate^a.

Entry	Ligand	Time (h)	Conv. (%)	anti/syn	yield (%)b
1c	–	24	70	43:57	61
2	DPBen	4	98	48:52	92
3	dppp	6	93	47:53	81
4	Dppf	9	67	34:66	58
5	Dppf	12	100	25:75	97
6d	Xantphos	6	100	24:76	98
7	Xantphos	4	99	28:72	93
8	DPEphos	4	84	36:64	76

^a2a:1d:PMHS:CuX:ligand =1:1.2:2:1%:1%, 25 °C unless noted, ^bisolated yield; ^c2a:1d:PMHS:CuX:ligand = 1:1.2:2:3%:3%; ^d2a:1d:PMHS:CuX:ligand = 1:1.5:3:3%:3%, 0 °C.