Tantalum Catalyzed Hydroaminoalkylation for the Synthesis of α- and β-Substituted N-Heterocycles

Unprotected secondary amines are directly alkylated by C-H functionalization adjacent to nitrogen, thereby opening new routes toward the synthesis of alpha- and beta-alkylated N-heterocycles. alpha-Alkylated piperidine, piperazine, and azepane products are prepared from heterocycles and alkenes in an atom-economic reaction with excellent regio- and diastereoselectivity. beta-Alkylated N-heterocycles are synthesized via a scalable one-pot alkylation/cyclization procedure generating 3-methylated azetidines, pyrrolidines, and piperidines.