1,2-Regioselective reduction of α,β-unsaturated carbonyl compounds with lithium aluminium hydride in the presence of lanthanoid salts

An α,β-unsaturated carbonyl compound when reduced by lithium aluminium hydride in the presence of lanthanoid chloride, bromide, iodide, or acetylacetonate gives, selectivity, an allylic alcohol, while in its absence saturated alcohol formation predominates. Such reactions can be applied to various α,β-unsaturated carbonyl compounds such as aldehydes, ketones, esters, and lactones. In addition to its wide applicability, this reagent appears to be easier to use, than other known reducing reagents.