Conformational equilibrium of 9-(2-acyloxyethyl)-1,4-dimethoxytriptycenes in chloroform-d suggests that the stability of the ±sc conformation increases as the electronegativity of the acyl group increases. The results together with other pertinent data are discussed from the stand point that there is an attractive interaction between the acyloxymethyl and the methoxyl groups in proximity. Reflecting its high ionization potential, the chloro group in 1-position showed no stabilization of the ±sc conformation, although mass spectra and some chemical properties indicate that there is an interaction between the chloro group and highly electronegative CH2X group. A possible correlation of these results with the incipient transition state for SN2 reactions is suggested.
氯仿-d中9-(2-酰氧乙基)-1,4-二甲氧基三苯烯的构象平衡表明,随着酰基电负性的增加,±sc构象的稳定性增加。这些结果与其他相关数据一起从以下观点进行讨论:在接近位置的酰氧甲基和甲氧基之间存在吸引力相互作用。由于其高电离势,1位的
氯原子没有表现出对±sc构象的稳定作用,尽管质谱和一些
化学性质表明
氯原子与高度电负性的CH2X基团之间存在相互作用。建议这些结果可能与SN2反应的初态过渡态有关。