Eicosanoids excessive synthesis

Synthesis of eicosanoid 555 commenced with a stereoselective organocatalytic cyclopropanation achieved by reacting bromoacetate 559 with Michael acceptor 560 in the presence of dimeric catalyst 561. As the authors were not able to resolve product 562 using an enantioselective HPLC phase, the exact enantiomeric excess could not be determined oti this stage but was found to be satisfactory for the rest of the sequence. With respect to the synthesis of lactonealdehyde 556, the cyclopropanation was carried out by adding the Weinreb- m dt 563 to enone 564 to furnish the key intermediate 565, which was transferred further into 556 in a similar manner (474) (Scheme 118). 

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