Ketones a,P-dianion

Table 2 lists examples of monoalkylation reactions of ketone a,p-dianions. The dianions always react with alkylating agents at the /3-carbon atom to generate the corresponding lithium enolates, which can be quenched by water or electrophiles such as TMSC1 and PhSSPh. The last two examples demonstrate the results of the single alkylation reaction of a ketone a,5-dianion with hexyl and allyl bromides, which occurs at the 5-position to give lithium Z-enolates. 

A higher-order cyanocuprate, R2Cu(CN)Li2, reacts with a, P-un saturated acylzirconocene chlorides at — 78 °C in THF to afford saturated ketones without giving a Michael-type product (Scheme 5.39). Treatment of the reaction mixture with D20 gives the a,P-dideut-erated ketone (of undetermined stereochemistry), and generation of a ketone a,P-dianion... 

---