Simultaneous Generation and Subsequent Cycloaddition of ortho-Quinonemethides and Cyclic Enecarbamates Promoted by a Gold/Lewis Acid Catalytic System

A new catalytic reaction to synthesize structurally complex hexahydrochromeno[2,3-b]pyrrole derivatives from simple 3-butynamine and 2-(hydroxymethyl)phenol derivatives is described. The process is promoted by a dual catalytic system formed by a gold complex and a Lewis acid (boron trifluoride). The reaction involves the synchronized transformation of the starting materials into two reactive intermediates, a cyclic enamine derivative and an ortho-quinone methide, that subsequently react between them through a formal [4+2] cycloaddition to furnish the final poly-heterocyclic product in a straightforward way.