Efficient Synthesis and Theoretical Study of Siloxy-Benzocyclooctenes: 7,8-Bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene and 6,9-Dimethyl-7,8-bis-trimethylsilanyloxy-5,6,9,10-tetrahydro-benzocyclooctene-6,9-dicarboxylic Acid Diethyl Ester
作者:Saeed A Fakhri、Behrooz H Yousefi
DOI:10.1016/s0040-4020(00)00715-8
日期:2000.10
structural features. The synthetic method involved is monoalkylation of malonic acid diethyl ester and 2-methyl-malonic acid diethyl ester with 1,2-bis-bromomethyl-benzene in DMSO, and yields esters 2 and 4, respectively. The decarboxylation of 2 by DMSO/LiCl in the presence of a very small amount of water yields diester 3. Compounds 3 and 4 undergo acyloin condensation to give siloxy-benzocyclooctenes
2- [2-(2,2-双-乙氧基羰基-乙基) -苄基]丙二酸二乙酯2,3- [2-(2-乙氧基羰基-乙基) -苯基] -丙酸乙酯3,2- [ 2-(2,2-双-乙氧基羰基-丙基) -苄基] -2-甲基-丙二酸二乙酯4,7,8-双-三甲基硅烷氧基- 5,6,9,10四氢苯并环辛烯5和6为了研究其光谱学和结构特征,已经合成了9,9-二甲基-7,8-双-三甲基甲硅烷基氧基-5,6,9,10-四氢-苯并环辛烯-6,9-二羧酸二乙酯6。涉及的合成方法是在DMSO中将丙二酸二乙酯和2-甲基-丙二酸二乙酯与1,2-双-溴甲基苯进行单烷基化,生成酯2和4, 分别。在少量水的存在下,通过DMSO / LiCl对2进行脱羧,可生成二酯3。化合物3和4进行酰氯缩合,分别得到甲硅烷氧基-苯并环辛烯5和6。双硅烷氧基-苯并环辛烯6的计算结构和参数表明4的环化与所用试剂数量无关的原因。