Direct and Regioselective Transformation of α-Chloro Carbonyl Compounds into Alkenes and Deuterioalkenes

Article abstract of DOI:10.1021/jo00326a024

The successive treatment ethyl chloroacetate or chloroacetyl chloride with Grignard reagents and lithium powder leads to symmetrical terminal olefins in a regioselective manner.The best results are obtained with acid chlorides.The influence of the temperature and the reaction time on overall yield of the process are studied; in general, yields are increased by working at low temperature (-60 deg C).Internally substituted olefins are obtained from α-chloro acid chlorides through a similar process.The treatment of α-chloro aldehydes, ketones and carboxylic acid derivatives (esters or acid chlorides) with lithium aluminium hydride or lithium aluminium hydride/aluminium chloride and lithium powder at low temperature (-60 deg C) leads in a regioselective manner to olefins with the same carbon skeleton as the starting carbonyl compound.Reactions with lithium aluminium deuteride lead to incorporation of deuterium at predetermined positions in the alkene.