3- Pentenone addition reaction

Michael Addition. Methallyl phenyl sulfone has been a good partner with a variety of different Michael receptors. Addition to enones using / BuLi as base at —78 °C gave the desired products in good yields. Methyl vinyl ketone afforded the Michael adduct in 61% yield (eq 7). Reaction of methallyl sulfone with 2-hexenone and 2-methyl-2-pentenone in the presence of HMPA provided the conjugate addition products in 91% yield and 79% yield, respectively (eqs 8 and 9).lO.Ha... 

Catalytic asymmetric Michael addition is an important reaction for creating carbon-carbon bonds with enantioselectivity. This reaction can be combined with other catalytic transformations to build up complex organic structures. A successful example is the enantioselective cascade Michael addition/H -hydrogenation catalyzed by ruthenium hydride borohydride complexes containing P-aminophosphine ligands 26 (Scheme 5.13) [19]. This approach has been extended to pentenones, heptenones, and nitrostyrene Michael acceptors and malonitrile Michael donors. 

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