Selective Piperidine Synthesis Exploiting Iodine-Catalyzed Csp3-H Amination under Visible Light

Abstract

A route to selective piperidine formation through intramolecular catalytic Csp3-H amination is described. This hydro- carbon amination reaction employs a homogeneous iodine catalyst derived from halogen coordination between molecular iodine and a terminal oxidant. It relies on visible light initiation and proceeds within two catalytic cycles that comprise a radical C-H func- tionalization and an iodine-catalyzed C-N bond formation. Under these conditions, the commonly observed preference for pyrroli- dine synthesis based on halogenated nitrogen intermediates within the Hofmann-Löffler domain is effectively altered in favor of a free radical promoted piperidine formation. The protocol is demonstrated for a total of 30 applications