Joint Research on Chemistry of Hypervalent Compounds

超价化合物的研究是有机化学最重要的领域之一。本研究旨在阐明高价化合物在有机反应中的作用，特别是开发新的反应性高价试剂以及使用这些试剂的合成反应。1.高价试剂的开发高反应性高价碘试剂的合成。以碘酰苯（PhIO）和三氟甲磺酸（TfOH）为原料合成了对亚苯基型双碘（III）试剂。TfOH的摩尔量的两倍对于产生对亚苯基试剂是必不可少的。通过使用2当量的TFOH将碘苯二乙酸盐转化为高反应性碘试剂。此外，邻碘酰苯甲酸提供了高反应性碘试剂。这些高价碘试剂对芳香族和炔属底物表现出高的反应活性，以高产率得到芳基和炔基碘鎓盐。2.高价碘化合物的高反应活性高价碘试剂的高反应活性归因于与碘连接的三氟甲磺酸酯基团的高离核性。芳环上的吸电子基团增加了反应活性。超价化合物对亲核试剂的高反应活性来源于苯基碘鎓基团的高离去能力。3.新型超价化合物的合成本研究开发的高反应活性超价试剂提供了许多新型超价化合物，如：（对亚苯基）二碘鎓盐，炔基碘鎓盐，二芳基碘鎓盐，具有羧基的芳基和炔基碘鎓盐，1-芳基苯并噻吩鎓盐，以及相关的衍生物。

The research on hypervalent compounds is the one of the most important fields of organic chemistry. This research was conducted to aim at clarifying the roles of hypervalent compounds in organic reactions, especially, to develope new reactive hypervalent reagents and the synthetic reactions using the reagents.1.Development of Hypervalent ReagentsSynthesis of highly reactive hypervalent iodine reagents were conducted. The p-phenylene type of bisiodine (III) reagents was prepared from iodosylbenzene (PhIO) and trifluoromethanesulfonic acid (TfOH). Double the molar amounts of TfOH were essential to produce the p-phenylene reagent. Iodobenzenediacetate was converted by using 2 equiv of TFOH to a highly reactive iodine reagent. Also, o-iodosylbenzoic acid provided a highly reactive iodine reagent. These hypervalent iodine reagents showed a high reactivity to aromatic and acetylenic substrates to give aryl and alkynyliodoniumu salts in high yields.2.High Reactivity of Hypervalent Iodine CompoundsThe high reactivity of the hypervalent iodine reagents was attributed to the high nucleofugacity of triflate group attached with iodine. The electron withdrawing groups on the aromatic ring increased the reactivity. The high reactivity of hypervalent compounds toward nucleophiles was derived from the high leaving ability of the phenyliodonio group.3.Synthesis of Novel Hypervalent CompoundsThe highly reactive hypervalent reagents developed in this research provided many novel hypervalent compounds, such as (p-phenylene) bisiodonium salts, alkynyliodonium salts, diaryliodonium salts, aryl-and alkynyliodonium salts with carboxy group, 1-arylbenzothiophenium salts, and the related derivatives, in addition to liquid-crystalline diacetylenes and benzyne precursors.