Stereoselective synthesis of alkylidene butenolides was achieved from (2Z,4E)-dienoic acids by a sequence involving halocyclisation and elimination reactions. Selectivity was found to be highly dependent on the nature of the substituents. This methodology has been applied to the synthesis of a retinoid containing the alkylidene butenolide core.
                                    通过涉及卤环化和消除反应的序列,从(2Z,4E)-二烯酸实现了亚烷基
丁烯内酯的立体选择性合成。发现选择性高度依赖于取代基的性质。该方法已应用于含有亚烷基
丁烯内酯核心的类
维生素A的合成。