Ring-expansion strategies are valuable synthetic tools that take benefit of existing ring structures and evade the unfavorable enthalpic-and entropic effects that arise with end-to-end cyclizations. One potentially important class of such reactions is the Dowd-Beckwith reaction, the ringexpansion of ketones via alkoxy radicals. The exciting advancement in this research area is starting to show its potential, as demonstrated by applying this methodology in strategy-level bond formation to synthesize complex natural products. This Review aims to provide the first comprehensive survey of the development of the Dowd-Beckwith reaction spanning three decades from the initial report to the present day, thus providing the readers with great detail about the contributions of this reaction to organic synthesis. We hope that this review will further disclose the salient features of the Dowd-Beckwith reaction for synthetic applications and encourage the development of new, more advanced applications.

A temperature-regulated catalyst-free photoinduced selective carbene C–H insertion strategy was realized to efficiently synthesize spiro-β-lactones and -lactams, which hold considerable promise in drug discovery programs. The reaction shows broad applicability across a range of α-diazo esters and amides with various ring sizes and substituents and has been demonstrated to successfully achieve the late-stage spirocyclization of natural/bioactive compounds. The obtained products could be transformed into spiro-oxetanes, -azetidines, and -cyclopropanes, privileged scaffolds with broad utility in medicinal chemistry.

Ring‐expansion strategies are valuable synthetic tools that take benefit of existing ring structures and evade the unfavorable enthalpic‐and entropic effects that arise with end‐to‐end cyclizations. One potentially important class of such reactions is the Dowd–Beckwith reaction. In their Review article (DOI: 10.1002/chem.202202025), Hari et al. discuss the origin and advancement of the Dowd–Beckwith reaction with particular focus on its application to complex natural products synthesis.