Photogenerated donor-donor diazo compounds enable facile access to spirocyclopropanes

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 & UDelta;1-pyrazoline intermediates. Notably, kinetic analysis enabled the isolation of intermediary spiro-heterocycles. 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.

Automated summary

Prompted by the increasing interest in strained hydrocarbons as potential drug candidates, the researchers developed a simple and efficient photochemical protocol for the synthesis of (spiro)cyclopropanes from stable tosylhydrazones and electron-poor olefins. This protocol involves a two-step one-pot transformation using donor-donor diazo compounds and subsequent nitrogen extrusion of the intermediate UΔ1-pyrazoline. Notably, kinetic analysis allowed for the isolation of intermediate spiro-heterocycles.