Synthesis of Spiro[benzo[ b ]thiophene-2(3 H ),1′-cyclopropan]-3-ones via Phosphine-Mediated [2 + 1] Cyclization and their Synthetic Transformations

),1'-cyclopropan]-3-ones. Subsequent derivatizations underscore its practical value in constructing fused dihydrofuran- or furanone-containing scaffolds. Both the cyclization and the downstream transformations proceed under mild conditions and tolerate a broad substrate scope.