Table 1.

entrya	allene	alkyne	yield (%)	1,4-dieneb
1	5; R1 = H	6	53	7c; R1 = H
2	8; R1 = Me		74	9; R1 = Me
3	10	6	64	11
4	12	6	87	13
5	14	6	53	15d
6	12	16	66	17e
7	8	18	48	19e
8	8	20	62	21f

^aTypical reaction conditions: alkyne (1.4 eq), Ti(Oi-Pr)₄ (2.1 eq), c-C₅H₉MgCl (4.2 eq), PhMe (−78 to −30 °C), cool to −78 °C then add allenyl alkoxide (1 eq), (−78 to 0 °C).

^bProducts formed as single olefin isomers unless otherwise noted.

^cFormed as a 3:1 mixture of products containing a minor cross-conjugated triene (see Supporting Information for details).

^dIn addition, 31% of a cross-conjugated triene was isolated from this reaction.

^ers = 4:1.

^frr = 2:1.