(E)-1-Bromo-3,3-diethoxy-1-propene (Diethyl Acetal of 3-Bromoacrolein). A Versatile Synthon for the Synthesis of Furans, Butenolides, and (Z)-Allyl Alcohols

Article abstract of DOI:10.1021/jo00224a044

A convenient preparation of the title compound allowed a study in which the α-lithio-α-bromovinyl acetal 2 could be evaluated as a precursor to furans, butenolides, and (Z)-allyl alcohols.Reaction of the lithio derivative with aldehydes, ketones, and alkyl halides took place in a convenient manner.The bromine was either transformed at a later stage to an alkyl group or reduced to hydrogen with tin hydrides.The carbonyl adducts of 2 could be transformed, on mild hydrolysis, to butenolides or 2,3-disubstituted furans.An interesting solvent system (1:1:1 THF-Et2O-pentane) allowed vinyl proton abstraction and halogen-metal exchange to take place in one pot.