Divergent oxidative annulation of primary aliphatic amines to access semi-saturated fused pyrimidines or quinazolines

Abstract

A novel multicomponent reaction has been developed for the divergent synthesis of semi-saturated fused pyrimidines. Readily available cycloalkylamines, aldehydes and ammonium iodide were directly assembled through oxidative annulation and β-C(sp³)–H functionalization of primary aliphatic amines under metal-free conditions. Moreover, employing an I₂/DMSO/O₂ oxidative system enabled the same multicomponent process to directly afford quinazoline derivatives via oxidative dehydrogenation without requiring intermediate isolation. This approach establishes a new pathway for constructing structurally diverse azaarenes through an oxidative annulation strategy that involves C(sp³)–H functionalization of primary aliphatic amines.