Synthesis of Medium and Large Ring Compounds, XLIII. Synthesis and Isomerization of 8,9-Dimethyl[6]paracyclophane and Its Bridged Dewar Isomer
作者:Werner Tochtermann、Lars Rodefeld、Herbert Dreeskamp、Stefan M. Sarge
DOI:10.1002/jlac.199619961203
日期:1996.12
An improved sonochemical procedure for the synthesis of dimethyl [6]paracyclophane-8,9-dicarboxylate (2a) on a 10-g scale is described. The title compound 2d was synthesized from 2a in three steps. Irradiation of 2d yielded the Dewar isomer 3. In solution, the reaction enthalpy for the thermal isomerization of 3 to 2d was determined to be -162 ± 16 kJ · mol-1, while the activation energy for this reaction
描述了一种改进的声化学程序,用于合成10-g规模的[6]对环二甲基8,9-二羧酸二甲酯(2a)。由三步法从2a合成标题化合物2d。辐照2d产生杜瓦异构体3。在溶液中,确定了3到2d的热异构化反应的焓为-162±16 kJ·mol -1,而该反应的活化能为123±12 kJ·mol -1。