Prostaglandins enantioselective Michael addition

Exo-methylene ketones like 536 readily undergo addition reactions of various copper-zinc reagents. This methodology has been applied for the synthesis of prostaglandines such as 537 (Scheme 2-152, eq. (a)). Moreover, enantioselective Michael-additions have been pioneered by Feringa et a/. " and Alexakis et Remarkably, only a catalytic amount of the chiral ligand 538 (4 mol%) and Cu(OTf)2 (2 mol%) was required, and the 1,4-addition product 539 was obtained with an enantiomeric excess of 93% ee (Scheme 2-152, eq. This method was used for an... 

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