Regioselective De Novo Synthesis of Cyanohydroxypyridines with a Concerted Cycloaddition Mechanism

An efficient cycloaddition reaction of 1-alkoxy-1-azadienes with α,α-dicyanoalkenes is described, which gives facile access to highly substituted 3-hydroxypyridines in very good yields and with complete regiocontrol and chemoselectivity. The reaction path was investigated in detail by quantum mechanics calculations, reporting that a concerted cycloaddition mechanism and thermodynamic control synergistically contribute to the observed selectivity.