Lithium dialkylcuprates: reaction with acid

Ethyl (5 )-3-hydroxybutanoate (3), obtained from the reduction of ethyl acetoacetate with bakers yeast, is readily converted into the tosylate (4). Its reaction with a lithium dialkylcuprate occurs with inversion of configuration to provide the acid (5) in 88—84% optical purity for three examples (Scheme 3). ... 

This procedure illustrates a new method for the preparation of 6-alkyl-a,g-unsaturated esters by coupling lithium dialkylcuprates with enol phosphates of g-keto esters. The procedure for the preparation of methyl 2-oxocyclohexanecarboxylate described in Part A Is based on one reported by Ruest, Blouin, and Deslongcharaps. Methyl 2-methyl-l-cyc1ohexene-l-carboxylate has been prepared by esterification of the corresponding acid with dlazomethane - and by reaction of methyl 2-chloro-l-cyclohexene-l-carboxyl ate with lithium dimethylcuprate. -... 

By derivatizing an a,p-unsaturated acid into the mono ester of chiral 1,1 -bi-8,8 -naphthol the reaction with lithium dialkylcuprates leads to saturated ketones containing chirality centers at the p-carbon atoms." Consecutive 1,4-addition and 1,2-addition account for this result. The alkyl transfer to enones from Grignard reagents under copper catalysis is subject to chiral modification, e.g., by the introduction of 56" or 57." ... 

Claisen rearrangement occurred on heating a l-cyclopropylprop-2-en-l-ol derivative in the presence of triethyl orthoacetate. 5, 2 reactions occurred on treatment of 4-oxat-ricyclo[3.3.0.0 ]oct-6-en-3-one with lithium dialkylcuprates to give a 4-alkylbicyclo[3.1.0]hex-2-ene-6-carboxylic acid. - ... 

Reaction of lithium dialkylcuprates with acid chlorides (17.2, 18.6, 22.10)... 

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