threo-3-Hydroxycarboxylic acids, which are stereoselectively obtained from metallated carboxylic acids and aldehydes, are converted into (Z)-olefins and enol ethers with the triphenylphosphine–diethyl azodicarboxylate-adduct, whereas the corresponding (E)-isomers are prepared via the β-lactones.
苏式-3-羟基
羧酸,其立体选择性
金属化,从
羧酸和醛而获得,被转换成(Ž)烯烃和烯醇与
三苯基膦-
偶氮二甲酸二乙酯加合物醚,而相应的(ë) -异构体,制备经由所述β-内酯。