Table 1.

Catalyst screening for the reaction of 1 a with allene 5 a.^[a]

Entry	Catalyst	6 a Yield [%][b]
1	A	74 (66)[c]
2	B	55
3	C	61
4	D	55
5	E	31
6	F	57
7	G	–[d]

[a] Reaction conditions: 1 a (0.1 m in DCE), 5 a (2.0 equiv), catalyst (5 mol %), 120 °C, 8 h. [b] The yield was determined by ¹H NMR spectroscopy with 1,3,5‐trimethoxybenzene as an internal standard. [c] The yield of the isolated product is given in parentheses. [d] Not detected. Cy=cyclohexyl, DCE=1,2‐dichloroethane, Tf=trifluoromethanesulfonyl.