Enantioselective Conjugate Addition - Auxiliary

Conjugate addition to alpha,beta-unsaturated carbonyls derived from Oppolzer's sultam

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Sn2

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The chelation of the carbonyl and sulfonyl oxygen to the magnesium cation restricts the rotation of the acrylamide portion and only S-cis conformation is energetically accessible. Conjugate addition of the organometallic then occurs with high selectivity from underneath to give the R enantiomer only.

 

 

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