Controlled synthesis of 1-vinylnaphthalenes versus (E)-α-(1,3-enyn-4-yl)-α,β-unsaturated esters from Morita–Baylis–Hillman bromides: a sequential alkynylation and competitive 6π-electrocyclization versus conjugative transposition of a triple bond

An expedient controlled synthesis of 1-vinylnaphthalenes and various dienyne derivatives has been carried out from the Morita–Baylis–Hillman bromides and propargyl acetate or p-nitrophenyl propargyl ether. By judicious choice of base, reaction temperature, and leaving group, a selective synthesis of 1-vinylnaphthalenes and dienynes, (E)-α-(1,3-enyn-4-yl)-α,β-unsaturated esters, could be performed.