Immobilized asymmetric catalyst and application thereof in asymmetric hydrogenation reaction

Abstract

The invention discloses an immobilized asymmetric catalyst. The immobilized asymmetric catalyst comprises a palladium-containing active component and an immobilized chiral assisting agent, wherein the immobilized chiral assisting agent loads chiral pyrrolidine or imidazolidine onto a high polymer, so that recycling can be favourably carried out, and good catalytic activity can be maintained. The invention also discloses an application of the immobilized asymmetric catalyst in an asymmetric hydrogenation reaction. The application of the supported asymmetric catalyst in the asymmetric hydrogenation reaction comprises the following steps of: dispersing alpha, beta-unsaturated aldehyde, the immobilized asymmetric catalyst and a catalytic amount of acid into a solvent for carrying out a reaction, and carrying out post-treatment at the end of the reaction, thus obtaining an asymmetric hydrogenation product. After the immobilized asymmetric catalyst is adopted, reaction selectivity is good, reaction conditions are mild, a preparation technology is simple, production cost is low, and the whole synthetic rout is environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of asymmetric synthesis, and in particular relates to a solid-supported asymmetric catalyst and its application in asymmetric hydrogenation reactions. Background technique [0002] D-citronellal (CAS: 2385-77-5), with the structure shown in formula (I), is a key intermediate in the field of fragrances and can be used to prepare various fragrances including L-menthol. D-citronellal is generally prepared by selectively reducing the carbon-carbon double bonds of α, β-unsaturated aldehydes. Among them, the catalytic hydrogenation reaction uses a small amount of homogeneous catalyst to hydrogenate the carbon-carbon double bonds with hydrogen. Auxiliaries, so as not to generate a lot of waste. Therefore, people have been trying to use hydrogen to asymmetrically hydrogenate the carbon-carbon double bonds of α,β-unsaturated aldehydes to obtain optically active D-citronellal. [0003] [0004] The synthetic meth...

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Problems solved by technology

[0011] In 2012, Japanese Takasago Company reported a method for preparing d-citronellal with pyrrolidine and palladium catalyzed citral, which solved the separation and utilization of citral, but due to pyrrolidine catalyst and waste It is dissolved together and cannot be extracted therefrom, so it still cannot solve the recycling problem of the catalyst, which makes the production cost too high and limits its application value (Shinya, Y et al.WO2012074075A1, 2012.), the synthetic method is as follows:

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