Decarbonylation with Wilkinson s catalyst

The desired synthon, acetonide 520, is prepared from carbonate 517 by treatment with acetone under acidic conditions. Alkylation of bicyclic lactone 521 with 520 affords 522 as a single isomer. Reduction of the lactone with DIBAL produces an equilibrium mixture of lactol and hydroxy aldehyde 523. Oxidation of the ally lie alcohol and decarbonylation with Wilkinson s catalyst furnishes the crucial enone intermediate 524 common to both natural products. 

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