Brønsted acid-catalyzed stereoselective [4+3] cycloadditions of ortho-hydroxybenzyl alcohols with N,N′-cyclic azomethine imines

The first [4+3] cycloaddition of ortho-hydroxybenzyl alcohols has been established to construct biologically important seven-membered heterocyclic scaffolds in good yields and excellent diastereoselectivities (up to 92% yield, most >95 : 5 dr).