Multicomponent Synthesis of Unsymmetrical 1,2-Diamines via Photo-Induced Carbonyl Alkylative Amination

Vicinal diamines (or 1,2-diamines) are privileged structural motifs present in many bioactive molecules and drug candidates. The past few decades have witnessed substantial progress on the synthesis of unsymmetrical 1,2-diamines via several strategies, including olefin diamination, α-amino carbanion- or radical-mediated Mannich reaction. However, methods for the one-step preparation of valuable N,N’-dialkylated 1,2-diamines are still rarely reported. We report herein a photo-induced carbonyl alkylative amination reaction that, for the first time, brings together amines, aldehydes, and iodoarenes under catalyst- and base-free conditions for the synthesis of diverse alkyl/aryl-substituted unsymmetrical 1,2-diamines. This method shows broad scope and good tolerance of functional groups. Furthermore, detailed mechanistic investigations reveal that the reaction proceeds via visible light-mediated radical chain process.