Table 1. Effect of steric bulk and hydrogen bonding on the aryne Alder-ene reaction.

^a20–25 mg scale of 1.

^bDetermined by ¹H NMR of crude mixtures.

^cIsolated yield.

^dDiastereomeric ratios.

^e52% yield with 75% conversion at 150 °C, 40 h.

^fDetermined by ¹H NMR with an internal standard.

^gStarting material intact at 130 °C but decomposed at 170 °C.

^hNo product observed with decomposition of the starting materials.

ⁱHeating at 90 °C.