Site-selective amination towards tertiary aliphatic allylamines

Aliphatic allylamines are widely used for the synthesis of diverse building blocks for agrochemicals and pharmaceuticals; there is therefore considerable interest in developing versatile and direct routes to aliphatic allylamines using common chemical feedstocks—olefins and amines. However, examples of such coupling reactions remain limited. It is even more challenging to achieve this goal with precise site control. Here we report that the combination of a photocatalyst and cobaloxime enables site-selective amination of olefins with secondary alkyl amines to afford allylic amines, eliminating the need for oxidants. This method is compatible with a broad scope of olefins and can be extended to achieve a site- and diastereoselective amination of terpenes. Mechanistic studies disclose that the reaction proceeds via a cobaloxime-promoted hydrogen atom transfer pathway to afford the product that results from cleavage of the stronger, primary allylic C–H bonds over other weaker allylic C–H bond options. Allylic amination of unactivated alkenes with aliphatic amines is a long-standing synthetic challenge in organic chemistry. This is now accomplished in an oxidant-free, site-selective process by using a combination of a photocatalyst and cobalt complex for the coupling of olefins and alkyl amines with hydrogen evolution.