Synthesis and reactions of .alpha.-chloro-.beta.,.gamma.-unsaturated esters. 2. Application to the synthesis of dihydrojasmone, cis-jasmone, desoxyallethrolone, and novel cyclopentenones
A facile access to indene frameworks through condensation of substituted cinnamylaldehydes and sulfonylamines under the catalysis of FeCl3 is reported.