Table 2.

Selective carbocyclization of allenynes 1 yielding borylated trienes 4^[a]

Entry	Allenyne	Product	4/5[b]	Yield of4[%],[c] ratio[b]
1			10:1	73
2			99:1	92
3			99:1	55 4 c/4 c′=2.4:1
4			9:1 >11:1	81 92[d]
5			18:1	65 4 e/4 e′=2.3:1
6			5:1	48 4 f/4 f′=1.4:1
7			>20:1	57

^[a]Unless otherwise noted, 1 (0.1–0.2 mmol), B₂pin₂ (1.3 equiv), Pd(OAc)₂ (2 mol %), BQ (1.1 equiv), and LiOAc⋅2 H₂O (20 mol %) were dissolved in DCE (5 mL mmol⁻¹) and stirred at 50 °C for 15 h.

^[b]The ratio was determined by ¹H NMR analysis of the reaction mixture.

^[c]Yield of the isolated product.

^[d]1 mmol of 1 d was used. E=CO₂Me.