A Novel Strategy for the Synthesis of Benzofuran Skeleton Neolignans: Application to Ailanthoidol, XH-14, and Obovaten
作者:Chai-Lin Kao、Ji-Wang Chern
DOI:10.1021/jo0258960
日期:2002.9.1
respectively. 15 and 33 were then cyclized in the presence of either mercury acetate in acetic acid or bromine in chloroform to give 3-chloromercurio- or 3-bromobenzofuran, respectively. The 3-chloromercurio intermediates could be reduced to proton or derivatized to ester or bromide, leading to the synthesis of ailanthoidol, XH-14, and obovaten, respectively. In addition, necleophilic substitution was used
开发了一种方便且通用的合成苯并呋喃骨架化合物艾蒽酚,XH-14和Obovaten的方法。从香兰素开始,一系列反应以71%的收率得到7。用正丁基锂处理7,然后加入取代的苯甲醛导致形成甲醇11和31。将由11和31氧化而得的取代的二苯甲酮用三甲基甲硅烷基重氮甲烷锂盐处理,分别得到二苯基乙炔15和33。然后在乙酸汞在乙酸中或溴在氯仿中的存在下将15和33环化,分别得到3-氯汞-或3-溴苯并呋喃。3-氯汞中间体可以还原为质子或衍生为酯或溴化物,分别导致合成艾兰醇,XH-14和Obovaten。另外,亲核取代被用于将甲酰基或甲基引入3-溴苯并呋喃衍生物中,从而提供了通往XH-14和Obovaten的替代途径。最终的延伸和脱保护反应以30、15和11%的产率分别提供了所需的艾兰酚,XH-14和obovaten。