Acetic acid-promoted cascade N-acyliminium ion/aza-Prins cyclization: stereoselective synthesis of functionalized fused tricyclic piperidines

Abstract

A novel acetic acid-promoted metal-free cascade N-acyliminium ion/aza-Prins cyclization of o-formyl carbamates and homoallylamines is reported. This one-pot protocol provides efficient and rapid access to masked cis-hydroxyhexahydropyrido[1,2-c]quinazolin-6-ones with concomitant generation of two stereogenic centers, four C–C/C–O/C–N bonds and two new rings in good yield and excellent diastereoselectivity.