Magnesium dicarboxylates promote the prenylation of phenolics that is extended to the total synthesis of icaritin
作者:Jichao Zhang、Wei Xiong、Yongju Wen、Xuewen Fu、Xiaoxia Lu、Guolin Zhang、Chun Wang
DOI:10.1039/d1ob02228h
日期:——
study of the prenylation provided evidence for the nucleophilic addition/substitution of the phenolic substrate to the alkyl halide in the presence of the magnesium dicarboxylates. The proto application of this method in the total synthesis of icaritin through the prenylation of 2,4,6-trihydroxyacetophenone, followed by the reaction with benzaldehyde to afford the flavonol, was successful, with a total
开发了由二羧酸镁促进的酚类底物的异戊烯化。对该范围的调查表明,具有给电子基团的底物比具有吸电子基团的底物产生更好的产率。尽管所有底物在 MeCN 中的转化率都高于 DMF,但 DMF 仍然是多酚底物的有利溶剂,因为 MeCN 会导致生成环化副产物 ( 6 ) 并降低3的收率。对于那些对位未占据的底物,邻位与对位异戊二烯化(3'与3'' )的区域选择性也与溶剂有关。DMF主要生产邻位-产品,但转化率低。另一方面,MeCN 主要产生对位产物,以及次要的邻位产物。异戊二烯化的机理研究为在二羧酸镁存在下酚底物亲核加成/取代到卤代烷提供了证据。该方法在2,4,6-三羟基苯乙酮异戊烯化后与苯甲醛反应得到黄酮醇的全合成淫羊藿苷中的初步应用是成功的,总收率为33%。