Friday, March 29, 2019

Enantioselective catalysis

In general, enantioselective catalysis (known traditionally as asymmetric catalysis) are chiral coordination complexes. Catalysis is effective for a broader range of transformations than any other method of enantioselective synthesis. The catalysts are almost invariably rendered chiral by using chiral ligands (it is also possible to generate chiral-at-metal complexes using simpler achiral ligands, but such species have rarely proven to be useful synthetically). Most enantioselective catalysts are effective at low substrate/catalyst ratios. Given their high efficiencies, they are often suitable for industrial scale synthesis, even with expensive catalysts. A versatile example of enantioselective synthesis is asymmetric hydrogenation, which is used to reduce a wide variety of functional groups.
Noyori Asymmetric Hydrogenation Scheme.png
The design of new catalysts is very much dominated by the development of new classes of ligands. Certain ligands, often referred to as 'privileged ligands', have been found to be effective in a wide range of reactions; examples include BINOL, Salen, and BOX. In general however few catalysts are effective at more than one type of asymmetric reaction. For example, Noyori asymmetric hydrogenation with BINAP/Ru requires a β-ketone, although another catalyst, BINAP/diamine-Ru, widens the scope to α,β-alkenes and aromatic chemicals.

BINAPs we are producing:
rac-BINAP, CAS: 98327-87-8
R-BINAP, CAS: 76189-55-4
S-BINAP, CAS: 76189-56-5
S-TolBINAP, CAS: 100165-88-6

Contact us: angus@sunfinelabs.com

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