Progress in Research on Co-catalyzed Synthesis of Chiral Cyanol Derivatives by Guyan Reagent and Bimetal

Progress in research on the synthesis of chiral cyanohydrin derivatives by co-catalysis of Guyan reagent and bimetals Active compounds are widely used in chemical and pharmaceutical synthesis. The catalytic asymmetric addition reaction of aldehydes with cyano compounds is an effective method for synthesizing optically active cyanohydrins and their derivatives. Commonly used catalysts include biocatalyst enzymes and synthetic chemical catalysts. The advantage of chemically catalyzed synthesis of optically active cyanohydrin derivatives is that it is easy to obtain two different chiral enantiomers. Although hundreds of catalysts have been reported, the current problem is the low efficiency and selectivity of the catalyst The harsh catalytic reaction conditions or the use of precious metal catalysts have affected its practical application. Researchers from the State Key Laboratory of Metal Organic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, based on the design concept of bimetallic co-catalysis, cleverly integrated two Salen-Ti units into the same molecule with an appropriate bridge chain to develop A high activity chiral bis-Salen-Ti complex catalyst bridged with cis-norbornene dicarboxylic acid is produced, which improves the catalytic efficiency by 1-2 orders of magnitude. When TMSCN is used as the cyanide reagent, the amount of catalyst can be reduced Up to 5 parts per million; when using cheap sodium cyanide as the cyanide reagent, the reaction can also achieve ideal results. The study found that by fine-tuning the bridge structure, the spatial orientation of the two Salen-Ti catalytically active units can be optimized, which can maximize synergy during the catalytic process, and on the basis of the greatly improved catalytic activity, the reaction The selectivity is significantly higher than when using the simple Salen-Ti catalyst (88%), reaching 97%. The optimized catalytic system not only has high catalytic activity and excellent enantioselectivity, but also has wide substrate applicability. Some reaction products are chiral drugs clopidogrel, propranolol and chiral pyrethrins. The key intermediate of pesticide synthesis shows a good industrial application prospect.

Outdoor Furniture

Outdoor furniture refers to furniture used for outdoor environment, mainly used for outdoor leisure, entertainment and dining activities. The classification of outdoor furniture can be divided according to the material, function and shape.

First, classification by material
1. Wooden outdoor furniture: Wooden outdoor furniture is usually made of natural wood, such as teak. Wooden furniture has a natural, rustic character and is suitable for outdoor Spaces such as gardens, terraces and courtyards.
2. Metal outdoor furniture: Metal outdoor furniture is usually made of iron, aluminum, stainless steel and other metal materials. Metal furniture has the characteristics of durability and stability, suitable for long-term use in outdoor environment.
3. Cloth outdoor furniture: Cloth outdoor furniture is usually made of waterproof, sun protection and other special treatment of fabric. Fabric furniture with soft, comfortable characteristics, suitable for use in outdoor leisure areas.

Second, Classification by function
1. Leisure Chair: Leisure chair is the most common kind of outdoor furniture, usually used for outdoor leisure, sunbathing and other activities. There are a variety of leisure chairs, folding chairs, recliners, rocking chairs and so on.
2. Dining Table And Chair: Dining table and chair are mainly used for outdoor dining, usually consisting of a table and several chairs. Dining tables and chairs of various styles, there are round tables, square tables, etc., suitable for different venues and the number of people dining needs.
3. Parasol: Parasol is used for outdoor shading, which can effectively block direct sunlight and provide a cool resting environment. There are various styles of sunshade umbrellas, including ordinary umbrellas, large umbrellas, and rotating umbrellas.

Third, Classification by shape
1. Chairs: including ordinary chairs, rocking chairs, recliners, etc., suitable for outdoor leisure and sun.
2. Table category: including dining table, coffee table, side table, etc., suitable for outdoor dining and placing items.
3. Sofa category: including single sofa, double sofa, combination sofa, etc., suitable for outdoor leisure and parties.
4. Reclining chairs: including hammocks, reclining chairs, etc., suitable for outdoor naps and rest.
5. Queue class: including benches, benches, etc., suitable for outdoor queuing and waiting.

In summary, the classification of outdoor furniture can be divided according to material, function and shape. Different outdoor furniture is suitable for different outdoor environment and activity needs, choose suitable outdoor furniture can provide comfortable and convenient outdoor life experience.

Outdoor Table,Rattan Table,Rattan Chair,Beach Furniture

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