Crotonic acid reaction with lithium

Reaction of a,P-unsaturated acids with ketones Lithium naphthalenide in the presence ofdiethylamine reacts with x,/ -unsaturated adds, for examplecrotonic acid (1), to give the a-anion of lithium crotonate. This anion reacts with ketones, for example cyclohexanone (2), to give d-hydroxy acids, for example 5(r-hydroxycyclohex-r-yl)-crotonic acid (3). 

Conjugate addition of the lithium dienolate derived from crotonic acid to diphenylpropenone produces mainly the 1,4-a-product 15 with R, R configuration. The reaction occurs via a regio- and diastereoselective tandem 1,2-addition/Cope rearrangement of the intermediate 13. If the reaction is carried out at — 90°C, the intermediate 1,2-y-adduct 14 can be isolated 1000. 

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