Transformation of Alcohols ; Development of Substitution of Hydroxyl Groups

醇是含量最丰富的化学物质，应可用于化学工业。然而，较低的羟基离开能力阻碍了醇基化学的发展。本研究采用铟硅复合体系实现了醇类化合物的催化还原。催化剂中的关键物种提供了原位硅上的Lewis酸中心。烷基化试剂与烯丙基硅烷、炔基硅烷或戊烯基硅烷具有广泛的用途。该体系具有较高的化学选择性，反应体系中含有酯基、卤基、硝基。所使用的溶剂可以是e上没有卤化的己烷，尽管其他人报道的例子应该使用卤化溶剂来催化乙醇取代。这一事实有力地促进了以环境为基础的工业化学。反应机理包括阳离子物种，因为叔醇在反应体系中表现出比其他醇更高的反应活性。因此，含有伯羟基和叔羟基的化合物能够很好地完成选择性烷基化反应，得到理想的产物。该系统也被应用于制糖化学。烯丙基硅烷催化取代糖衍生物，无需任何保护步骤，可一步合成资源天然产物。即使底物醇含有二茂铁部分(金属有机部分)，反应也能有效进行，对金属中心没有任何影响。上述结果显示了以醇为原料制备碱性化学品的实际和工业应用。这一过程在未来将是理想和有前途的。

Alcohols are the most abundant chemicals and should be useful for chemical industry. However, low leaving ability of OH groups retards the development of chemistry based on alcohols. In this research, catalytic subsutition of alcohols was accomplished using indium-silicon combined system. The key species in the catalyst supplies Lewis acid center on silicon in situ. The alkylation reagens have wide application with allylsilane, alkynylsilane, or prennylsilanes. This system showed high chemoselectivity; ester, halo, nitro groups were intert to the reaction system. The used solvent can be hexane that is not halogenated on e although the reported examples by others should use halogenated solvents for catalytic alcohol substitution. This fact strongly contributes to the industrial chemistry based on environmental aspects. The reaction mechanism includes cationic species as a ke y intermediate because tertiary alcohols showed higher reactivity than other alcohols in the reaction system. Therefore, selective alkylation for the compounds bearing primary and tertiary OH groups was well accomplished to give the desired product. This system was also applied to the sugar chemistry. The catalytic substitution of sugar-derivatives by allylsilane in a catalytic manner gave a resource natural product in one-step without any protecting procedures. Even the substrate alcohol has ferrocenic moiety (organometallic part), the reaction proceeded effectively without any effect on the metallo sites. The results described above shows the practical and industrial application for preparation of basic chemicals starting from alcohols. The process will be t he ideal and promising in a future.