Synthesis of alkylidenecyclopropanes via thermal cycloreversion of α-spirocyclopropyl-β-lactones

Article abstract of DOI:10.1055/s-1997-6134

An efficient two-step synthesis of alkylidenecyclopropanes is reported based on the addition of metallated cyclopropyl thiol esters to carbonyl compounds. Thermolysis of the resulting α-spirocyclopropyl-β-lactones at 105-150°C induces thermal [2+2] cycloreversion to furnish alkylidenecyclopropanes in good yield.