Table 2.

Optimization of the phosphine oxide^a

entry	R3P=O	mol%	% yieldb	% eec
1	Ph3P=O	20	63	79
2	(2-furyl)3P=O	20	67	68
3	TDMPPOd	20	61	57
4	(n-Bu)3P=O	20	58	54
5	(R)-BINAPOe	10	74	51
6	(S)-BINAPOe	10	78	47
7		10	57	48

^aReaction as shown in eq 4 with 1 equiv of octanal, 3 equiv of diyne 4, 10 mol% 1 and 3 equiv of Me₂Zn.

^bIsolated yield of diynol 5.

^cEnantiomeric excess of 5 determind by chiral HPLC.

^dTDMPPO = tris(2,6-dimethoxyphenyl)phosphine oxide.

^eBINAPO = 2,2'-bis(diphenylphosphoryl)-1,1'-binaphthyl.