Bromine addition to α-(1-hydroxyalkyl)- and α-(1-alkoxyalkyl)-α,β-unsaturated esters, an approach to hydroxyfimbrolide and bromobeckerelide

Article abstract of DOI:10.1016/S0040-4020(01)89031-1

Conventional ionic bromination of electron-poor olefins, 2-(1-hydroxyalkyl)- and 2-(1-alkoxyalkyl)propenoates, 2b-d, and methyl (E)-2-(1-hydroxyethyl)-2-butenoate, 3a, proceeds with yields higher than 80%. Treatment of (E)-3-bromo-2-[1-(2-methoxyethoxy)methoxy]butyl]propenoic acid, 16, with two equivalents of strong bases, reaction related with a possible hydroxyfimbrolide and bromobeckerelide synthesis, resulted in the halogen-metal exchange reaction affording the acrylic acid 18, presumably through the generation of dianion 19.