Stereocomplementary Construction of Optically Active Bicyclo[4.3.0]nonenone Derivatives.

Treatment of (5S,6S)-5,6-bis(tert-butyldimethylsiloxy)-8-(substituted)oct-1-en-7-yne derivatives, prepared from diethyl L-tartrate, with Co(2)(CO)(8) afforded the corresponding cobalt-complexed enynes, which were subsequently exposed to the typical Pauson-Khand conditions to furnish highly stereoselectively or exclusively (2S,3S,6S)-2,3-bis(tert-butyldimethylsiloxy)-9-(substituted)bicyclo[4.3.0]non-1(9)-en-8-ones. On the other hand, (3S,4S)-1-(substituted)oct-7-en-1-yne-3,4-diol congeners produced, on exposure to the Pauson-Khand conditions, (2S,3S,6R)-2,3-dihydroxy-9-(substituted)bicyclo[4.3.0]-non-1(9)-en-8-one derivatives in a highly stereoselective manner. The newly developed procedure has been shown to be useful for construction of the 2,3-bis(oxygenated)-7-(substituted)bicyclo[4.3.0]non-6-en-8-one framework in a stereocomplementary as well as stereoselective fashion.