Method for preparing alcohol compound based on zinc acetate catalytic carbonyl reduction

Abstract

The invention discloses a method for preparing an alcohol compound based on zinc acetate catalytic carbonyl reduction, which comprises the following steps: by taking zinc acetate as a catalyst and pinacol borane as a hydrogen source, stirring and reacting at room temperature without adding an expensive ligand, thereby obtaining a hydrogenated product. The method has the advantages of low cost, short reaction time, mild reaction conditions, high selectivity and the like, and special equipment such as hydrogen and a high-pressure kettle and high-temperature conditions are avoided. The method is suitable for selective hydrogenation of different substituted aldehyde / ketone derivatives and other aromatic heterocyclic aldehyde substrates.

Description

technical field [0001] The invention relates to a highly selective hydrogenation method for a class of aromatic aldehydes and ketones. Background technique [0002] Alcohol compounds are chemical intermediates in the synthesis of natural products, drugs, pesticides and functional materials, and are often used as auxiliaries and ligands in organic synthesis reactions. Direct reduction of carbonyl groups from aldehydes and ketones is one of the most common strategies for the preparation of alcohols. At present, the reduction methods that have been reported include: metal hydrides, boron-based reagents, catalytic hydrogenation, and biomimetic reduction methods. [0003] In 2006, Kim's research group used HgCl 2 As a catalyst, 10 equivalents of magnesium metal is used as an additive, ethanol is used as a solvent, and the reaction takes 12 hours to realize the reduction of ketones to alcohols at room temperature. Although the reaction system is suitable for aliphatic and aromat...

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Problems solved by technology

[0003] In 2006, Kim's research group used HgCl 2 As a catalyst, 10 equivalents of magnesium metal is used as an additive, and ethanol is used as a solvent. After 12 hours of reaction, ketones are reduced to alcohols at room temperature. Although the reaction system is suitable for aliphatic and aromatic ketones, due to the presence of a large amount of magnesium Exist, not well compatible for some reductive functional groups, easily generate the by-product of reduction coupling, the reaction time is too long in addition, the problem such as productive rate moderate limits the further application of this method (Tetrahedron.Lett.2006,47,9- 12)

[0009] The above methods have the disadvantages of requiring chemical equivalent catalysts and precious metals, long reaction time, strict conditions, and complicated operations, which bring certain environmental pollution and economic cost problems, especially in large-scale industrial production processes.

At present, the stable pinacol borane is used as the hydrogen source to realize the selective hydrogenation of aromatic aldehydes and ketones under the catalysis of transition metals. Most systems need a large amount of strong acid and strong base to hydrolyze the reaction intermediate hydroboration compound to realize the carbonyl group. Hydrogenation, the experimental steps are relatively cumbersome, which increases the cost of the reaction to a certain extent. Therefore, it is of great scientific research significance to develop a cheap and highly selective method to reduce carbonyl substances to achieve the preparation of alcohols.

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