Transformation of Alcohols ; Development of Substitution of Hydroxyl Groups

醇类是最丰富的化学品，对化学工业应该是有用的。然而，OH基团的低离去能力阻碍了基于醇的化学的发展。本研究采用铟硅复合体系催化取代醇类化合物。催化剂中的关键物种原位提供硅上的刘易斯酸中心。烷基化试剂与烯丙基硅烷、炔基硅烷或异戊二烯基硅烷具有广泛的应用。该体系具有很高的化学选择性，酯基、卤基、硝基均不参与反应。使用的溶剂可以是在e上不卤化的己烷，尽管其他人报道的实施例应该使用卤化溶剂用于催化醇取代。这一事实有力地促进了基于环境方面的工业化学。反应机理包括阳离子物种作为关键中间体，因为叔醇在反应体系中显示出比其他醇更高的反应活性。因此，带有伯和叔OH基团的化合物的选择性烷基化得到了所需的产物。该系统也被应用于糖化学。利用烯丙基硅烷对糖衍生物进行催化取代反应，不经任何保护步骤，一步合成了资源性天然产物。即使底物醇具有二茂铁部分（有机金属部分），反应也有效地进行，对金属位点没有任何影响。上述结果显示了从醇开始制备基本化学品的实际和工业应用。该工艺是一种理想的、有前途的工艺。

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.