Treatment of o-(1, 7-octadiynyl) benzoyldiazoethane with rhodium (II) octanoate in pentane resulted in a double internal/internal alkyne insertion reaction producing a labile bicyclo [4.1. 0] hept-1 (7)-ene derivative which readily undergoes a Diels-Alder reaction with diphenylisobenzofuran. Changing the solvent from pentane to CH2Cl2 afforded a 2: 1 mixture of cis-and trans-alkenyl-substituted indenones. Stepwise cyclization involving a ...
