The sequence of a stepwise AdE reaction and intramolecular Pauson-Khand cycloaddition as an entry into the synthesis of polycyclic compounds

A stepwise Ad E acylmethoxylation across the double bond of dicobalt hexacarbonyl complexes (DCHCC) of conjugated enynes was elaborated as an efficient and general route for the synthesis of DCHCC of 1,6-enynes containing a combination of five- and six-membered-ring fragments. Depending on the structure of these adducts, the latter either were subjected to 1,2-carbonyl reduction followed by an intramolecular Pauson-Khand (IMPK) cyclization or were directly utilized as substrates for this process