Recifeiolide synthesis

For the recifeiolide synthesis, the oxazole carbanion was alkylated with iodo THP ether (340) (an 85 15 mixture of (E)- and (Z)-isomers). Acid hydrolysis of the THP group, photooxygenation and cyclization gave a mixture of (E)- and (Z)- ( )-recifeiolide (341) from which the pure (E)-form could be isolated by chromatography on silver nitrate-impregnated silica gel (Scheme 74). 

Recifeiolide synthesis (cyclization reaction based on a nucleophilic attack of a jr-allyl Pd intermediate). 

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