Table 4. Reaction Scope with Optimized Protocol.

entry	R1	R2	R3	methoda	5:6 (% yield)
1	Ph	Ph	Me	Ab	>98:2 (82)
2	4-FC6H4	Ph	Me	A	93:7 (85)
3	n-Hept	Ph	Me	A	>98:2 (77)
4	c-Hex	Ph	Me	A	>98:2 (90)
5	Ph	i-Bu	Et	A	94:6 (86)
6	n-Hept	i-Bu	Et	A	93:7 (66)
7	Ph	n-Pr	Et	A	68:32 (56)
8	2-furyl	n-Pr	Me	A	93:7 (76)
9	Ph	i-Pr	Me	A	>98:2 (78)
10	c-Hex	i-Pr	Me	A	>98:2 (75)
11	Ph	i-Pr	H	B	>98:2 (61)
12	Ph	n-Hex	H	B	95:5 (69)

^aMethod A: i-Pr₃SiH as reductant, reaction conducted at 0.125 M in the aldehyde and alkyne at 50 °C. Method B: t-Bu₂MeSiH as reductant, reaction conducted at 0.0125 M in the aldehyde and alkyne with 22 mol % Ni(COD)₂ at rt.

^bConducted at 0.0125 M in the aldehyde and alkyne.