Intramolecular photochemical [2 + 1]-cycloadditions of nucleophilic siloxy carbenes†

<jats:p>Visible light induced singlet nucleophilic carbenes undergo rapid [2 + 1]-cycloaddition with tethered olefins to afford unique bicyclo[3.1.0]hexane and bicyclo[4.1.0]heptane scaffolds.</jats:p>