212121-62-5

Upstream product

• 81477-94-3 N-(diphenylmethylene)glycine tert-butyl ester 
• 292638-85-8 acrylic acid methyl ester 

Downstream Products

• 79640-72-5 L-glutamic acid 1-tert-butyl ester 5-methyl ester 
• 138-15-8 l-glutamic acid hydrochloride 
• 7776-34-3 L-proline hydrochloride 
• 2812-46-6 proline tert-butyl ester 
• 91229-86-6 tert-butyl (S)-2-<(tert-butyloxycarbonyl)amino>-5-bromopentanoate 
• 56-87-1 L-lysine 

Relevant academic research and scientific papers

Modified guanidines as chiral superbases: Application to asymmetric Michael reaction of glycine imine with acrylate or its related compounds

Modified guanidines efficiently catalysed the asymmetric Michael reaction of a prochiral glycine derivative with acrylate or its related compounds either in solution or without a solvent under simple and mild conditions (> 95% ee).

Application scope and limitations of TADDOL-derived chiral ammonium salt phase-transfer catalysts

We have recently introduced a new class of chiral ammonium salt catalysts derived from easily available TADDOLs. To get a full picture of the scope of application and limitations of our catalysts we tested them in a variety of different important transformations. We found that, although these compounds have recently shown their good potential in the asymmetric α-alkylation of glycine Schiff bases, they clearly failed when we attempted to control more reactive nucleophiles like β-keto esters. On the other hand, when using them to catalyse the addition of glycine Schiff bases to different Michael acceptors it was found necessary to carefully optimize the reaction conditions for every single substrate class, as seemingly small structural changes sometimes required the use of totally different reaction conditions. Under carefully optimized conditions enantiomeric ratios up to 91:9 could be achieved in the addition of glycine Schiff bases to acrylates, whereas acrylamides and methyl vinyl ketone gave slightly lower selectivities (up to e.r. 77:23 in these cases). Thus, together with additional studies towards the syntheses of these catalysts we have now a very detailed understanding about the scope and limitations of the synthesis sequence to access our PTCs and about the application scope of these catalysts in asymmetric transformations.

Enantioselective solution- and solid-phase synthesis of glutamic acid derivatives via Michael addition reactions

The enantioselective conjugate addition of Schiif base ester derivatives to Michael acceptors either in solution (56-89% e.e.) or on solid-phase (34-82% e.e.) gave optically active unnatural α-amino acid derivatives. The reaction was conducted in the pres

Chiral calcium complexes as bronsted base catalysts for asymmetric addition of α-amino acid derivatives to α,β-unsaturated carbonyl compounds

A novel catalyst system based on complexes of calcium which promote the catalytic asymmetric 1,4-addition reactions and [3+2] cycloaddition reactions of α-amino acid derivatives with α,β-unsaturated carbonyl compounds have been developed. The reactions proceeded smoothly in the presence of 5-10 mol % of the chiral calcium catalyst to afford the desired adducts in high yields with high diastereo- and enantioselectivities. A wide range of α,β-unsaturated esters and amides were applicable, and other glycine and even dl-alanine derivatives reacted with several α,β-unsaturated carbonyl compounds to afford the corresponding substituted pyrrolodine derivatives in high yields with excellent diastereo- and enantioselectivities. In the reactions with dl-alanine derivatives, quaternary asymmetric carbons were constructed efficiently. Copyright

Expanding the Toolbox of Heterogeneous Asymmetric Organocatalysts: Bifunctional Cyclopropenimine Superbases for Enantioselective Catalysis in Batch and Continuous Flow

A strategy for the immobilization of chiral 2,3-bisaminocyclopropenium salt (pre-catalyst) onto polystyrene and silica supports is presented together with a suitable procedure for the conversion into the corresponding cyclopropenimine superbase catalysts.

Highly Enantioselective Conjugate Addition of Glycine Imines to Activated Alkenes Catalyzed by Amino-Acid-Derived Chiral Phosphonium Salts

Chiral quaternary phosphonium salts derived from amino acids were readily prepared and employed as phase-transfer catalysts for the highly enantioselective conjugate addition of glycine imines to various activated alkenes, including chalcones, acrylates, and vinyl ketones.

Structure-activity relationship studies of cyclopropenimines as enantioselective Bronsted base catalysts

We recently demonstrated that chiral cyclopropenimines are viable Bronsted base catalysts in enantioselective Michael and Mannich reactions. Herein, we describe a series of structure-activity relationship studies that provide an enhanced understanding of the effectiveness of certain cyclopropenimines as enantioselective Bronsted base catalysts. These studies underscore the crucial importance of dicyclohexylamino substituents in mediating both reaction rate and enantioselectivity. In addition, an unusual catalyst CH...O interaction, which provides both ground state and transition state organization, is discussed. Cyclopropenimine stability studies have led to the identification of new catalysts with greatly improved stability. Finally, additional demonstrations of substrate scope and current limitations are provided herein.

Design of chiral urea-quaternary ammonium salt hybrid catalysts for asymmetric reactions of glycine Schiff bases

Bifunctional chiral urea-containing quaternary ammonium salts can be straightforwardly synthesised in good yield and with high structural diversity via a scalable and operationally simple highly telescoped sequence starting from trans-1,2-cyclohexanediamine. These novel hybrid catalysts were systematically investigated for their potential to control glycine Schiff bases in asymmetric addition reactions. It was found that Michael addition reactions and the herein presented aldol-initiated cascade reaction can be carried out to provide enantiomeric ratios up to 95:5 and good yields under mild conditions at room temperature.

Transition state analysis of enantioselective br?nsted base catalysis by chiral cyclopropenimines

Experimental 13C kinetic isotope effects have been used to interrogate the rate-limiting step of the Michael addition of glycinate imines to benzyl acrylate catalyzed by a chiral 2,3-bis(dicyclohexylamino) cyclopropenimine catalyst. The reaction is found to proceed via rate-limiting carbon-carbon bond formation. The origins of enantioselectivity and a key noncovalent CH?O interaction responsible for transition state organization are identified on the basis of density functional theory calculations and probed using experimental labeling studies. The resulting high-resolution experimental picture of the enantioselectivity-determining transition state is expected to guide new catalyst design and reaction development.

Chiral octahedral complexes of cobalt(III) as "organic catalysts in disguise" for the asymmetric addition of a glycine schiff base ester to activated olefins

Stereochemically inert and positively charged chiral complexes of cobalt(III) prepared from Schiff bases derived from chiral diamines and salicylaldehydes were shown to be efficient catalysts of the benchmark asymmetric phase-transfer Michael addition of nine activated olefins to O'Donnell's substrate. The reaction products had enantiomeric purities of up to 96%. DFT calculations were invoked to rationalize the stereochemistry of the addition.