Conformational Effects in Diastereoselective Aryne Diels−Alder Reactions: Synthesis of Benzo-Fused [2.2.1] Heterobicycles

It was found that the diastereoselectivity of the Diels−Alder reaction between arynes and substituted furans is highly sensitive to substitution, which affects the reactive conformation. By varying the location of the groups on the diene partner, it is possible to obtain both excellent chemical yields and high stereoselectivity. This methodology offers rapid and convenient access to enantiomerically pure bicyclic scaffolds which are difficult to prepare by other means.