New Synthetic Approaches to the Seven-Membered Oxocarbon

从振动谱的研究结果表明，单环氧碳离子C_nO_n^<2-> (n=3-6)是对称的D_<nh>结构。然而，更高的同源物C_7O_7^<2->是一个未知的物种。本课题以合成C_7O_7^<2->为主要目的，重点研究了在七元环上引入含氧官能团及其有效氧化成多酮类物质。在此过程中，虽然C_7O_7^<2->的合成尚未成功，但以下有趣的结果已被披露；它们是：a)在溶剂溶解条件下制备多乙酰氧基和多羟基tropone； b) 2-乙酰氧基tropone的乙酰性的机理证据；c)功能化对对苯二酚的氧化电位估计；d)阳极氧化法制备对苯二酚缩醛；e) 4,4,5,5-四甲基环庚-2,6-二烯酮的构象分析和光重排。

Monocyclic oxocarbon dianions C_nO_n^<2-> ( n=3-6 ) have been expressed to be symmetric D_<nh> structures from the results of a study of vibrational spectra. The higher homologue C_7O_7^<2->, however, is an unknown species. The main purpose in this research project was the synthesis of C_7O_7^<2-> species and intensive efforts were focussed on 1) introductions of oxygenated functional groups to the seven-membered ring and 2) their effective oxidations to polyketonic species.In the process, although the synthesis of C_7O_7^<2-> species has not succeeded yet, following intriguing results were disclosed; they were a) preparations of polyacetoxy- and polyhydroxytropones by solvolytic reaction conditions, b) mechanistic evidences for an acetotropy in 2-acetoxytropones, c) an estimation of oxidation potentials of functionalyzed p-tropoquinones, d) preparations of tropoquinone acetals by anodic oxidations, and e) the conformational analysis and photorearrangements of 4,4,5,5-tetramethoxycyclohepta-2,6-dienones.