61347-76-0

Upstream product

• 492-41-1 (1R,2S)-norephedrine 
• 100-52-7 benzaldehyde 
• 3198-15-0 (1R,2S)-(-)-norephedrine hydrochloride 
• 100-39-0 benzyl bromide 
• 204644-95-1 (1S,2R)-[PhCHNCH(Me)CH(OH)Ph] 
• 100-46-9 benzylamine 
• 579-07-7 1-Phenylpropane-1,2-dione 
• 90-63-1 (RS)-1-hydroxy-1-phenylpropan-2-one 
• 67-56-1 methanol 
• 70735-98-7 (+/-)-4r-methyl-2ξ,5t-diphenyl-oxazolidine 
• 52597-17-8 2-(N-benzylamino)-1-phenyl-1-propanone 
• 64-17-5 ethanol 
• 2114-00-3 2-bromo-1-phenyl-1-propanone 
• 25438-37-3 phenyl(trimethylsiloxy)acetonitrile 

Downstream Products

• 190724-36-8 Benzyl-((1S,2R)-2-hydroxy-1-methyl-2-phenyl-ethyl)-carbamic acid ethyl ester 
• 198906-14-8 (2R,4S,5R)-2-Chloro-3-benzyl-4-methyl-5-phenyl-1,3,2-oxazaphospholidin-2-one 
• 613688-62-3 [benzyl[(1S,2R)-2-hydroxy-1-methyl-2-phenylethyl]amino]acetonitrile 
• 613688-63-4 [benzyl[(1S,2R)-2-chloro-1-methyl-2-phenylethyl]amino]acetonitrile 
• 613688-64-5 (2S,3S,4S)-1-benzyl-4-methyl-3-phenylazetidine-2-carbonitrile 
• 613688-75-8 (S)-2-[((2R,3S,4S)-1-Benzyl-4-methyl-3-phenyl-azetidine-2-carbonyl)-amino]-propionic acid methyl ester 
• 613688-74-7 (S)-2-[((2S,3S,4S)-1-Benzyl-4-methyl-3-phenyl-azetidine-2-carbonyl)-amino]-propionic acid methyl ester 
• 117693-80-8 (+/-)-3-benzyl-4r-methyl-2ξ,5t-diphenyl-oxazolidine 

Relevant academic research and scientific papers

N-Pyridylmethylephedrine derivatives in the catalytic asymmetric addition of diethylzinc to aldehydes and diphenylphosphinoylimines

N-Pyridylmethyl-substituted Ephedra derivatives were synthesized by either direct alkylation or reductive alkylation of (1R,2S)-norephedrine, (1S,2S)-pseudo norephedrine, and (1R,2S)-ephedrine. These derivatives were then employed in asymmetric addition reactions with diethylzinc and aldehydes and diphenylphosphinoylimines. The use of the diastereomers from the Ephedra family allowed for a systematic evaluation of the contribution of the N-pyridylmethyl.

Design of a genetic algorithm for the simulated evolution of a library of asymmetric transfer hydrogenation catalysts

A library of catalysts was designed for asymmetric-hydrogen transfer to acetophenone. At first, the whole library was submitted to evaluation using high-throughput experiments (HTE). The catalysts were listed in ascending order, with respect to their performance, and best catalysts were identified. In the second step, various simulated evolution experiments, based on a genetic algorithm, were applied to this library. A small part of the library, called the mother generation (GO), thus evolved from generation to generation. The goal was to use our collection of HTE data to adjust the parameters of the genetic algorithm, in order to obtain a maximum of the best catalysts within a minimal number of gen-erations. It was namely found that simulated evolution's results depended on the selection of GO and that a random GO should be preferred. We also demonstrated that it was possible to get 5 to 6 of the ten best catalysts while investigating only 10% of the library. Moreover, we developed a double algorithm making this result still achievable if the evolution started with one of the worst GO.

β-Amino alcohols derived from (1R,2S)-norephedrine and (1S,2S)-pseudonorephedrine as catalysts in the asymmetric addition of diethylzinc to aldehydes

A family of N-alkylnorephedrine and N-alkylpseudonorephedrine derived ligands were prepared and applied in the asymmetric alkylation of benzaldehyde using diethylzinc. The absolute configuration of the addition product was directed primarily by the benzylic position of the Ephedra alkaloid, while the magnitude of the enantiomeric ratio was heavily influenced by the nitrogen substituent. However, sterically demanding substituents at the nitrogen position caused the enantioselectivity to be the same for the two diastereomeric systems. Among the ligands that were prepared, it was determined that the N-cyclooctylpseudonorephedrine derivative 7b yielded the highest enantiomeric ratios (87.5:12.5 to 91.0:9.0) when applied in the catalytic asymmetric addition of diethylzinc to aldehydes.

Salicylaldehyde based oxazolidines as catalysts for the asymmetric addition of diethylzinc to aldehydes

(Chemical Equation Presented) A series of oxazolidines have been prepared by condensation of N-isopropyl norephedrine with a variety of salicylaldehyde derivatives. Despite the stereochemical relationship of (1R,2S)-norephedrine with (1R,2S)-ephedrine, th

Diastereoselective reduction of α-aminoketones: Synthesis of anti- and syn-β-aminoalcohols

Reduction of N-t-BOC-protected-N-alkyl α-aminoketones with LiEt 3BH or Li(S-Bu)3BH furnishes protected syn-β-aminoalcohols with high selectivities. In contrast, removal of the BOC group followed by reduction of the aminoketone gives anti-β- aminoalcohols with variable selectivities. With aromatic ketones, selectivities are typically high while aliphatic ketones show mediocre to high selectivities depending on steric considerations.

Diastereoselectivity in the reduction of α-oxy- and α-amino-substituted acyclic ketones by polymethylhydrosiloxane

Diastereoselectivity in the reduction of α-alkoxy-, α-acyloxy-, and α-alkylamino-substituted ketones with polymethylhydrosiloxane (PMHS) in the presence of fluoride ion catalysis was investigated. High syn-selectivity was observed in the reduction of α-alkoxy, α-acyloxy, and α-dialkylamino ketones. Reduction of α-monoalkylamino ketone proceeded in anti-selective manner with moderate selectivity. The observed selectivity is explained based on Felkin-Anh and Cram-chelate models.

The use of benzamide derivatives of secondary amines for stereochemical studies by circular dichroism

The benzamide chromophore is widely used as a Cottonogenic derivative of primary amines for stereochemical studies by circular dichroism. The assignments based on the exciton chirality method are reliable since the benzamide group has well-defined geometry and conformation. A recent report U.D. Chisholm, J. Golik, B. Krishnan, J.A. Matson, D.L. Van Vranken, J. Am. Chem. Soc. 1999, 121: 3801-3802) claimed a caveat in the application of the exciton chirality method to benzamides derived from secondary amines. By the use of benzoyl derivatives of amino alcohols (1-4) and diamines (5, 6) of known absolute configuration we demonstrate that the 250-210 nm range exciton Cotton effects due to secondary and tertiary benzamides are generally of opposite sign. The origin of such disparity is traced to different conformational equilibria of the amide C-N bond in secondary and tertiary benzamides, as shown by semiempirical molecular modelling and NMR data. This feature can be useful in the determination of absolute configuration by analysis of the CD spectra due to exciton coupling of tertiary benzamides.

PROCESS FOR PRODUCING L-ERYTHRO-(1R,2S)-2-AMINO-1-PHENYLPROPAN-1-OL

An efficient process for stereoselectively producing L-erythro-(1R,2S)-2-amino-1-phenylpropan-1-ol from L-(R)-phenylacetylcarbinol, which comprises reductively aminating L-(R)-phenylacetylcarbinol with a primary aralkylamine under catalytic reduction conditions and successively subjecting the resultant L-erythro-(1R,2S)-2-(N-aralkylamino)-1-phenylpropan-1-ol to catalytic reduction to remove the N-aralkyl group in a manner as in hydrogenolysis.

Stereoselective synthesis of δ-lactones from 5-oxoalkanals via one-pot sequential acetalization, tishchenko reaction, and lactonization by cooperative catalysis of samarium ion and mercaptan

By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) δ-lactones in efficient and stereoselective manners. This one-pot procedure comprises a sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis of optically active δ-lactones. This study also demonstrates the synthesis of two insect pheromones, (2S,5R)-2-methylhexanolide and (R)-hexadecanolide, as examples of a new protocol for asymmetric reduction of long-chain aliphatic ketones.

Amino alcohol coordination in ruthenium(II)-catalysed asymmetric transfer hydrogenation of ketones

The nature of ruthenium-amino alcohol precursors in the catalytic cycle of asymmetric hydrogen transfer reactions was studied using two C2- symmetrical tetradentate ligands (1 and 2) that were synthesised from (nor)ephedrine. The structure of t