Dioxinone conjugate additions

Conjugate addition of dialkylcuprates to the homochiral dioxinone (57), prepared from (/ )-3-hydroxy-butyric acid (56), produces single diastereomers (58), which can be hydrolyzed to the homochiral products (59).60 61 The overall process (Scheme 22) constitutes an example for self-regeneration of a stereogenic center . Interestingly, the high stereoselectivity can not be attributed to simple steric effects. 

The aj -unsaturated system of dioxinones can undergo conjugate addition by organocopper... 

Scheme 4.12. Asymmetric conjugate addition of cuprates to dioxinones [134].

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