Enynones, cyclic, addition

A highly stereo- and regio-selective 1,4-addition of Grignard reagents to cyclic enynones with excellent ee values (up to 97%) for an all-carbon quaternary stereocentre has been developed. The use of Cu(OTf)2 and A-heterocyclic carbene ligand 0 (14) as the catalyst combination led to the unique formation of the 1,4-adduct. 

Scheme 49 Copper-NHC-catalysed ECA of Grignard reagents to cyclic enynones that bear additional unsaturations by Alexalds [84]...

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