Chiral Synthesis

1. Chiral Synthesis The mirror image of a chiral molecule can be termed as enantiomer. As exhibited as below, a pair of enantiomers is structurally symmetrical but not completely coincident in chemistry. Chiral synthesis, is also called enantioselective synthesis, plays an essential role in the discovery of innovative drugs and materials and has been widely used in the development of pharmaceutical products and other biologically active substances. For example, axially chiral biaryls is one of the most important activity structures of many drug molecules. It can be synthesized by metal-mediated cross coupling metal-mediated cross coupling, de novo construction of an aromatic ring, point-to-axial chirality transfer or an atropselective transformation of an existing biaryl. Methods of Chiral Synthesis

2. Biocatalysis Biocatalysis is a method that performs chemical transformations using biological compounds from isolated enzymes to living cells. Biocatalysts are commonly used in industry for their advantages. Yeast is a typical biocatalyst for the chiral reduction of ketones. Chiral pool synthesis Chiral pool synthesis is one of the simplest approaches for chiral synthesis. A chiral starting material is manipulated through successive reactions, often by achiral reagents, to obtain the desired target molecule. So, chiral pool synthesis is necessary if a new chiral species would be created in SN2 reaction. Enantioselective catalysis Generally, enantioselective catalysis involves chiral coordination complexes. The catalysts are rendered chiral by using chiral ligands. A typical example of enantioselective catalysis is asymmetric hydrogenation, which could reduce a wide range of functional groups. Chiral auxiliaries

3. A chiral auxiliary is an organic compound that has the ability to attach to the starting material to form a new compound. Then it can undergo chiral reactions via intramolecular asymmetric induction. At the end, the auxiliary will be removed under conditions that will not cause racemization of the product. Organocatalysis Organocatalysis is a catalysis that increases the rate of a chemical reaction but the catalyst only consists of carbon, hydrogen, sulfur and other non-metal elements. If the organocatalyst is chiral, enantioselective synthesis can be achieved. Our Services Chiral Auxiliaries The Chiral auxiliary is a compound or unit that is temporarily added to organic synthesis in order to control the synthesis of stereochemistry. By adding the chiral auxiliary, the prochiral substrate can be transformed into a chiral product. Moreover, through an auxiliary recycle, the auxiliary can be typically recovered for future use. Chiral Building Blocks Building block is a term in chemistry which is used to describe a virtual molecular fragment or a real chemical compound the molecules of which possess reactive functional groups. As for chiral building blocks, they are valuable intermediates in the syntheses of natural products and pharmaceuticals. Chiral Catalysts Chiral catalysts can be applied in asymmetric synthesis such as alkylation, Diels-Alder reaction, asym-metric reduction, hydroformylation, epoxylation, dihydroxylation. The relationship

4. between the chiral catalyst and the reaction system is just like the relationship between the lock and the key, which is highly selective. Chiral Ligands The design of chiral ligands is frequently based on C2-symmetry in order to reduce the number of diastereomeric intermediates and transition states which play a role in the catalytic cycle. Chiral Resolution The Chiral resolution, as an important tool in the production of optically active drugs, is a process for the separation of racemic compounds into their enantiomers in the aspect of stereochemistry. At BOC Sciences, we can provide various types of methods including biocatalysis, chiral pool synthesis, enantioselective catalysis, chiral auxiliaries, and organocatalysis. We also use multiple techniques (NMR, LCMS, GCMS, X-ray) to analyze compounds after the chiral synthesis completed. Our experts will work with you to optimize the synthetic route and approaches. Additionally, according to your needs and the properties of chemical substances, a wide range of custom services are available in our laboratory. Reference 1. Jolliffe, J. D., Armstrong, R. J., & Smith, M. D. (2017). Catalytic enantioselective synthesis of atropisomeric biaryls by a cation-directed O-alkylation. Nature Chemistry, 9(6), 558. 2. Silverman, R. B., & Xue, F. (2015). U.S. Patent No. 9,212,161. Washington, DC: U.S. Patent and Trademark Office. https://www.bocsci.com/solutions/chiral-synthesis.htm