35799-87-2

Upstream product

• 66299-28-3 (Z)-2-acetylamino-4-methyl-pent-2-enoic acid methyl ester 
• 23032-21-5 D-leucine methyl ester 
• 830-03-5 4-nitrophenol acetate 
• 57289-25-5 methyl N-acetyl-leucinate 
• 186581-53-3 diazomethane 
• 64896-30-6 (Z)-2-Acetylamino-4-methyl-pent-2-enoic acid 
• 66299-27-2 methyl 2-(acetylamino)-4-methylpent-2-enoate 

Downstream Products

• 133467-01-3 methyl (2R)-2-(tert-butoxycarbonylamino)-4-methylpentanoate 

Relevant academic research and scientific papers

Engineering a polymeric chiral catalyst by using hydrogen bonding and coordination interactions

(Chemical Equation Presented) Noncovalent interactions are used to generate a polymeric supramolecular chiral catalyst (see picture). This heterogeneous catalyst, which is based on Feringa's MonoPhos/RhI system, is formed by orthogonal self-ass

Application of chiral mixed phosphorus/sulfur ligands to enantioselective rhodium-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation processes

Chiral mixed phosphorus/sulfur ligands 1-3 have been shown to be effective in enantioselective Rh-catalyzed dehydroamino acid hydrogenation and ketone hydrosilylation reactions (eqs 1, 2). After assaying the influence of the substituents at sulfur, the substituents on the ligand backbone, the relative stereochemistry within the ligand backbone, and the substituents at phosphorus, ligands 2c (R = 3,5-dimethylphenyl) and 3 were found to be optimal in the Rh-catalyzed hydrogenation of a variety of α-acylaminoacrylates in high enantioselectivity (89-97% ee). A similar optimization of the catalyst for the Rh-catalyzed hydrosilylation of ketones showed that ligand 3 afforded the highest enantioselectivities for a wide variety of aryl alkyl and dialkyl ketones (up to 99% ee). A model for asymmetric induction in the hydrogenation reaction is discussed in the context of existing models, based on the absolute stereochemistry of the products and the X-ray crystal structures of catalyst precursors and intermediates.

Catalytic asymmetric hydrogenation of α-(acetamido)acrylates using TRAP trans-chelating chiral bisphosphine ligands: Remarkable effects of ligand P-substituent and hydrogen pressure on enantioselectivity

The catalytic asymmetric hydrogenation of α-(acetamido)acrylates was carded out with the rhodium complexes prepared from [Rh(cod)2]BF4 and trans-chelating chiral bisphosphine ligands, (S,S)-2,2'-bis[(R)-1-(dialkylphosphino)ethyl]-1,1

Pronase catalysed peptide syntheses

A mixture of proteases from Streptomyces griseus (pronase), displaying a very broad substrate tolerance in the hydrolysis of peptides, has been studied for the first time systematically regarding their substrate specificity in peptide synthesis. It is demonstrated that pronase can be employed successfully for the formation of dipeptides with yields up to 95%. Pronase has also been employed successfully as catalyst for the enzyme assisted synthesis of a hexapeptide.

Carbohydrate Phosphinites as Practical Ligands in Asymmetric Catalysis: Electronic Effects and Dependence of Backbone Chirality in Rh-Catalyzed Asymmetric Hydrogenations. Synthesis of R- or S-Amino Acids Using Natural Sugars as Ligand Precursors

Vicinal diarylphosphinites derived from carbohydrates are excellent ligands for the Rh(I)-catalyzed enantioselective asymmetric hydrogenation of dehydroamino acid derivatives, producing the highest enantioselectivity of any ligands directly prepared from natural products. The enantioselectivity can be enhanced by the appropriate choice of substituents on the aromatic rings of the phosphinites. For example, the use of phosphinites with electron-donating bis(3,5-dimethylphenyl) groups on phosphorus provides ee's up to 99% for a wide range of amino acids including some with easily removable N-protecting groups. Electron-withdrawing aryl substituents, on the other hand, decrease the enantioselectivity. Sense of chiral induction in the amino acid product depends on the relative juxtaposition of the vicinal diphosphinites on a given sugar backbone. When readily available D-glucopyranosides are used as the starting sugars, 2,3-phosphinites give the S-amino acids and 3,4-phosphinites give the R-amino acids. In the case of aromatic and heteroaromatic amino acids, enantioselectivities > 95% are consistently obtained. Practical considerations such as the ease of ligand synthesis, rates of reactions, catalyst turnover, and scope and limitations in terms of substrates are discussed. A possible explanation for the enhancement of enantioselectivity by electron-rich phosphinites is offered.

Catalysis by β-cyclodextrin in the reaction of p-nitrophenyl acetate with α-amino acids

The reactions of p-nitrophenyl acetate, 1, with both enantiomers of the following α-amino acids: alanine (2a), methionine (2b), leucine (2c), and tryptophan (2d), were studied in the presence of β-cyclodextrin (β-CD).All the reactions were catalyzed by β-

Catalytic Asymmetric Hydrogenation of Methyl (E)- and (Z)-2-Acetamido-3-alkylacrylates

Rhodium-chiral phosphine complex catalyzed homogeneous hydrogenations of methyl (Z)- and (E)-2-acetamido-4-methoxybut-2-enoates ((Z,E)-10), methyl (Z)- and (E)-2-acetamidohex-2-enoates ((Z,E)-16A) and methyl (Z)- and (E)-2-acetamido-4-methylpent-2-enoates ((Z,E)-16B) are reported.With phosphines in which two achiral phosphorus atoms are connected by a chiral four-carbon unit, higher product enantiomeric excesses (ee's) are obtained from E than from Z substrates.With phosphines in which a two-carbon chiral unit separates two achiral phosphorus atoms, Z substrates are preferred.With dipamp (28), both Z and E substrates (particularly (Z,E)-16A) are reduced with high enantioselectivity.The additional oxygen atom in substrates (Z,E)-10 has little effect on product ee with most phosphines.