Formal Cycloadditions Driven by the Homolytic Opening of Strained, Saturated Ring Systems

The field of strain-driven, radical formal cycloadditions is experiencing a surge in activity motivated by a renaissance in free radical chemistry and growing demand for sp(3)-rich ring systems. The former has been driven in large part by the rise of photoredox catalysis, and the latter by adoption of the Escape from Flatland concept in medicinal chemistry. In the years since these broader trends emerged, dozens of formal cycloadditions, including catalytic, asymmetric variants, have been developed that operate via radical mechanisms. While cyclopropanes have been studied most extensively, a variety of strained ring systems are amenable to the design of analogous reactions. Many of these processes generate lucrative, functionally decorated sp(3)-rich ring systems that are difficult to access by other means. Herein, we summarize recent efforts in this area and analyze the state of the field.

Automated summary

The field of strain-driven, radical formal cycloadditions is undergoing a surge in activity, driven by the rise of photoredox catalysis and the demand for sp(3)-rich ring systems. This area has seen significant progress in recent years, with the development of various reactions and the generation of valuable sp(3)-rich ring systems.