Conjugate addition of carbon nucleophiles to a,P-unsaturated sulfoxides

1 Conjugate Addition of Carbon Nucleophiles to a p-Unsaturated Sulfoxides 

80% yield R R B n C4Hg, 73% yield R=f-C4H9,45% yield 

Spry has reported that cis-P-halo-a,P-unsaturated sulfoxides, on treatment with Grignard reagents, react to form carbon-sulfur bonds, and has used this methodology as part of the preparation of 5(l)-C(2)-secocephems [70], while Posner found that a,P-unsaturated aryl sulfoxides were easily reduced to the corresponding sulfides upon treatment with ethylmagnesium bromide/10% cuprous iodide with retention of double bond stereochemistry [71]. 

Few further examples of asymmetric Michael addition to acyclic a,P-unsaturated sulfoxides have appeared compared with the corresponding additions to the cyclic sulfoxides. 

Improvements in the diastereoselectivity of conjugate addition of organometallic reagents to optically pure 2-sulfinyl-2-cycloalkenones (pentenones and hexenones) 

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