Tertiary amines as a C1 synthon: metal-free synthesis of quinolines and 2-substituted quinolines via [3+2+1] aerobic cyclization and C–N bond cleavage

Abstract

An I₂-mediated [3+2+1] aerobic cyclization reaction of anilines with alkynes and tertiary amines without any peroxides has been reported. This protocol employed tertiary amines as a C1 building block for the direct synthesis of 2-non, 2-alkyl, and even 2-aryl substituted quinolines via C–N bond cleavage. Differing from the traditional methods, both terminal and internal alkynes were compatible in this metal-free three-component system. It is possible that the 2-vinylbenzenamine species might be produced as one of the active intermediates in this process.