摘要：

π-Allylnickel bromide complexes react with ketones and aldehydes to produce homoallylic alcohols, α diketones are the most reactive substrates, leading to α-keto homoallylic alcohols. Aldehydes and alicyclic ketones including some steroidal ketones are also reactive, while aliphatic acyclic ketones and α,β-unsaturated ketones react only sluggishly under forcing conditions. With conjugated ketones exclusive 1,2 attack results, even in the presence of added CuI. The reaction of α-(2-carbethoxyallyl)nickel bromide with ketones and aldehydes leads to α-methylene-γ-butyrolactones. Other carbonyl functional groups such as acid chlorides, esters, and amides, as well as nitriles and epoxides, are relatively unreactive. Thus π-allylnickel bromide complexes are less reactive and more selective than the corresponding allylzinc reagents toward carbonyl compounds, and are of potential synthetic utility.

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