Exploiting Imine Photochemistry for Masked N-Centered Radical Reactivity

Abstract

This report details the development of a masked N-centered radical strategy that harvests the energy of light to drive the conversion of cyclopropylimines to 1-aminonorbornanes. This process employs the N-centered radical character of a photoexcited imine to facilitate the homolytic fragmentation of the cyclopropane ring and the subsequent radical cyclization sequence that forms two new C-C bonds en route to the norbornane core. Achieving bond-forming reactivity as a function of the N-centered radical character of an excited state Schiff base is unique, requiring only violet light in this instance. This methodology operates in continuous flow, enhancing the potential to translate beyond the academic sector. The operational simplicity of this photochemical process and the structural novelty of the (hetero)aryl-fused 1-aminonorbornane products are anticipated to provide a valuable addition to discovery efforts in pharmaceutical and agrochemical industries.

Keywords: 1-aminonorbornane; N-centered radical; cyclopropylimine; excited state diyl; imine photochemistry.