Kim Jung Won, Koike Takeshi, Kotani Miyuki, Yamaguchi Kazuya, Mizuno Noritaka
Department of Applied Chemistry, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Chemistry. 2008;14(13):4104-9. doi: 10.1002/chem.200701917.
Reduction of allylic alcohols can be promoted efficiently by the supported ruthenium catalyst Ru(OH)x/Al2O3. Various allylic alcohols were converted to saturated alcohols in excellent yields by using 2-propanol without any additives. This Ru(OH)x/Al2O3-catalyzed reduction of a dienol proceeds only at the allylic double bond to afford the corresponding enol, and chemoselective isomerization and reduction can be realized under similar conditions. The catalysis is truly heterogeneous and the high catalytic performance can be maintained during at least three recycles of the Ru(OH)x/Al2O3 catalyst. The transformation of allylic alcohols to saturated alcohols consists of three sequential reactions: oxidation of allylic alcohols to alpha,beta-unsaturated carbonyl compounds; reduction of alpha,beta-unsaturated carbonyl compounds to saturated carbonyl compounds; and reduction of saturated carbonyl compounds to saturated alcohols.
负载型钌催化剂Ru(OH)x/Al2O3能够有效地促进烯丙醇的还原反应。使用2-丙醇且无任何添加剂时，各种烯丙醇能以优异的产率转化为饱和醇。这种Ru(OH)x/Al2O3催化的二烯醇还原反应仅在烯丙基双键处进行，生成相应的烯醇，并且在相似条件下可实现化学选择性异构化和还原反应。该催化反应是真正的多相催化反应，Ru(OH)x/Al2O3催化剂在至少三次循环使用过程中仍能保持高催化性能。烯丙醇向饱和醇的转化包括三个连续反应：烯丙醇氧化为α,β-不饱和羰基化合物；α,β-不饱和羰基化合物还原为饱和羰基化合物；饱和羰基化合物还原为饱和醇。
