Wednesday, April 24, 2019

Buchwald Hatwig Amination Reaction and The Phosphine Ligands

The Buchwald–Hartwig amination is a chemical reaction used in organic chemistry for the synthesis of carbon–nitrogen bondsvia the Palladium-catalyzed coupling reactions of amines with aryl halides. Although Pd-catalyzed C-N couplings were reported as early as 1983, Stephen L. Buchwald and John F. Hartwig have been credited, whose publications between 1994 and the late 2000s established the scope of the transformation. The reaction's synthetic utility stems primarily from the shortcomings of typical methods (nucleophilic substitution, reductive amination, etc.) for the synthesis of aromatic C–N bonds, with most methods suffering from limited substrate scope and functional group tolerance. The development of the Buchwald–Hartwig reaction allowed for the facile synthesis of aryl amines, replacing to an extent harsher methods (the Goldberg reaction, nucleophilic aromatic substitution, etc.) while significantly expanding the repertoire of possible C–N bond formation.

There is a list of phosphine ligands that we are offering for this noble reaction.
XPhos, CAS: 564483-18-7
SPhos, CAS: 657408-07-6
RuPhos, CAS: 787618-22-8
BrettPhos, CAS: 1070663-78-3

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

Wednesday, March 27, 2019

Intermediate For Chlorantraniliprole (CAS No. 500011-86-9)

Chlorantraniliprole is an insecticide of the ryanoid class. 

It is a carboxamide resulting from the formal condensation of the carboxylic acid group of 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid with the primary amino group of 2-amino-5-chloro-N,3-dimethylbenzamide.
500011-86-9

3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid

CAS: 500011-86-9
Purity: 95%+
Capacity: 20-30 Metric Tons Monthly



Contact Angus Li (E-mail: angus@sunfinelabs.com) for more details.