作者:Ronald J. Weagley、Harry W. Gibson
DOI:10.1055/s-1986-31698
日期:——
Dimethyl and diethyl 2,2,4,4-tetramethylglutarates have been synthesized in greater than 92% yield by lithium diisopropylamide promoted methylation of the ester enolates of 2,4-dimethyl- and 2,2-dimethyl-glutaric acids. 1, 3-Dimethoxycarbonyl-1,3-dimethylcyclopentane was prepared in 84% yield by dimethylation of the corresponding diester. The latter dialkylation occurs in one step using two equivalents of base followed by two equivalents of methyl iodide, while the former requires a two step procedure, introducing one methyl group at a time.
通过二异丙基酰胺锂促进 2,4 二甲基戊二酸和 2,2 二甲基戊二酸酯烯醇的甲基化,合成了 2,2,4,4-四甲基戊二酸二甲酯和二乙酯,收率超过 92%。通过对相应的二酯进行二甲基化反应,制备出了 1,3-二甲氧基羰基-1,3-二甲基环戊烷,收率为 84%。后者的二烷基化只需一步,使用两个当量的碱和两个当量的碘甲烷,而前者则需要两步,每次引入一个甲基。