Table 2.

Copper-catalyzed asymmetric 1,4-hydrosilylation of 1,3-enynes^a

entry	ligand (5 mol %)	T/ oC	t/h	6aa		7aa
				yield %	ee %	yield %
1	L1*	40	1	44	1	trace
2	L2*	40	1	10	−12	3
3	L3*	40	1	24	−19	trace
4	L4*	40	1	10	−32	1
5	L5*	40	1	54	43	trace
6	L5*	0	1	42	68	trace
7	L5*	−10	1	23	73	trace
8	L5*	−20	2	38	79	trace
9	L5*	−30	11	60	85	trace
10	L5*	−50	11	75b	96	trace
11	L5*	−50	11	78 (72)b,c,d	96	trace

^aReaction conditions: Cu(OAc)₂ (5 mol %), ligand (5 mol %), 1a (0.2 mmol) and 2a were stirred in DCE (1 mL) under nitrogen atmosphere, the yields were determined by crude ¹H NMR using 1,1,2,2-tetrachlorethane as an internal standard.

^b1a and 2a were added under −35 °C.

^cDCE = 2 mL, PhSiH₃ = 2.0 equiv.

^dIsolated yield.