Lithium alkyl mono-carbonate

A widely exploited procedure for bringing about carbenoid reactions of organic mono- and fifem-dihalides is by use of lithium alkyls. Examples are given in equations (11) and (12). Dimeric olefin formation, stereospecific cyclopropane formation from olefins, and insertion into carbon-hydrogen bonds have all been observed in suitable cases, together with further reactions of these products with excess of the lithium alkyl. 

Formally related reactions are observed, when anthracene [184] or arylolefines [185] are reduced in the presence of carbonic acid derivatives such as anhydrides, esters, amides, or nitriles. Under these conditions, mono- or diacylated compounds are obtained. It is interesting to note that the yield of acylated products largely depends on the counterion of the reduced hydrocarbon species. It is especially high when lithium is used, which is supposed to prevent hydrocarbon species. It is especially high when lithium is used, which is supposed to prevent hydrodimerization by ion pair formation. In contrast to alkylation, acylation is assumed to prefer an 8 2 mechanism. However, it is not clear if the radical anion or the dianion are the relative species. The addition of nitriles is usually followed by hydrolysis of the resulting ketimines [185]. 

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." ... 

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