Synthesis of medium-ring lactones via tandem methylenation/Claisen rearrangement of cyclic carbonates
作者:Edward A Anderson、James E.P Davidson、Justin R Harrison、Paul T O'Sullivan、Jonathan W Burton、Ian Collins、Andrew B Holmes
DOI:10.1016/s0040-4020(02)00049-2
日期:2002.3
vinyl-substituted 6- and 7-membered cyclic carbonates into 8- and 9-membered medium-ring lactones has been achieved in good yield using dimethyltitanocene in toluene at reflux. The reaction proceeds by initial formation of a ketene acetal which undergoes subsequent in situ Claisen rearrangement to provide the corresponding lactones. The preparation of the cyclic carbonates is carried out under basic conditions
使用二甲基噻吩并茂在甲苯中回流,可以很好地实现乙烯基取代的6-和7-元环状碳酸酯向8和9-元中环内酯的转化。该反应通过最初形成乙烯酮缩醛而进行,该酮缩醛经历随后的原位克莱森重排以提供相应的内酯。环状碳酸酯的制备是在基本条件下进行的,因此,该方法是对我们现有的基于硒的中环内酯合成方法的补充。