Photogenerated donor-donor diazo compounds enable facile access to spirocyclopropanes

Chem Commun (Camb). 2023 Oct 4;59(79):11835-11838. doi: 10.1039/d3cc03581f.

Abstract

Prompted by the increasing interest in strained hydrocarbons as potential drug candidates, we developed a simple and efficient photochemical protocol for (spiro)cyclopropanes from bench stable tosylhydrazones and electron poor olefins. This two-step one-pot transformation proceeds by (3+2)-cycloaddition of in situ formed donor-donor diazo compounds, followed by nitrogen extrusion of the Δ1-pyrazoline intermediates. Notably, kinetic analysis enabled the isolation of intermediary spiro-heterocycles.