93303-74-3

Upstream product

• 37577-28-9 (1S,2R)-(+)-norphedrine 
• 100-44-7 benzyl chloride 
• 100-46-9 benzylamine 
• 579-07-7 1-Phenylpropane-1,2-dione 
• 90-63-1 (RS)-1-hydroxy-1-phenylpropan-2-one 
• 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 
• 532-28-5 (RS)-mandelonitrile 
• 100-52-7 benzaldehyde 
• 698352-11-3 2-(N-benzyl-N-tert-butoxycarbonylamino)-1-phenyl-1-propanone 
• 698351-56-3 benzyl-(2-hydroxy-1-methyl-2-phenyl-ethyl)-carbamic acid tert-butyl ester 
• 1798-60-3 (R)-1-hydroxy-1-phenyl-2-propanone 

Downstream Products

• 1225561-69-2 (4R,5R)-3-benzyl-4-methyl-5-phenyloxazolidin-2-one 
• 1225561-65-8 (4R,5S)-3-benzyl-4-methyl-5-phenyloxazolidin-2-one 
• 1225562-05-9 benzyl[(1S,2R)-1-hydroxy-1-phenylpropan-2-yl]carbamoylazide 
• 117693-80-8 (+/-)-3-benzyl-4r-methyl-2ξ,5t-diphenyl-oxazolidine 
• 154257-51-9 (3R,4S)-3-methyl-4-phenyl-3,4-dihydroisoquinoline 
• 154334-44-8 (3R,4S)-3-Methyl-4-phenyl-1,2,3,4-tetrahydro-isoquinoline 

Relevant academic research and scientific papers

Asymmetric Epoxidation of Unfunctionalized Olefins Using Novel Chiral Dihydroisoquinolinium Salts as Organocatalysts

Abstract: Two new non-racemic chiral dihydroisoquinolinium salts with N-substituents bulkier than a methyl group have been synthesized from (1S,2R)-norephedrine. These salts were used to catalyze asymmetric epoxidation of a series of prochiral olefins. One of the two new catalysts provided higher enantioselectivities (up to 66% ee) than the reference salt containing an N-methyl substituent.

Enantioselective diethylzinc addition to the exocyclic C{double bond, long}N double bond of some 4-arylideneamino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-one derivatives

4-Arylideneamino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-ones 2a-f have been evaluated as substrates in the enantioselective diethylzinc addition reaction in the presence of (1S,2R)-N-alkyl-N-benzylnorephedrines 3a-d as chiral ligands. The utility of using a dual catalytic system (amino alcohol/halosilane) for the diethylzinc addition reaction has been also examined. The addition products 4-(1-arylpropyl)amino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-ones 4a-f were obtained in high yields and with enantiomeric excesses of up to 92%. The treatment of arylimines 2a-f with a diethylzinc reagent did not affect the hetero-ring opening although the C{double bond, long}N double bond of the lateral chain did undergo an addition reaction to yield the C-ethylated products 4a-f. The reductive cleavage of the 1,2,4-triazinyl heterocyclic ring from addition products 4a-f led smoothly to the corresponding free primary amines 5a-f without a significant loss of enantiomeric purity.

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.

(β-amino alcohol)(arene)ruthenium(II)-catalyzed asymmetric transfer hydrogenation of functionalized ketones - Scope, isolation of the catalytic intermediates, and deactivation processes

The asymmetric transfer hydrogenation of functionalized ketones with (β-amino alcohol)(arene)RuII catalysts using 2-propanol as the hydrogen source has been studied. The structure of the catalyst has been systematically screened using a wide variety of [(η6-arene)RuCl2]2 complexes and β-amino alcohols R1CH(OH)CHR2NHR3, some of which were specifically designed for optimized performance, e.g. (1S,2R)-N-(4-biphenylmethyl)norephedrine (9ο). The efficiencies of the catalytic combinations have been evaluated in the reduction of β-oxo esters and ketones bearing heteroatoms at the α-position. The catalyst precursor [{η6-p-cymene}{η2-N,O-(9ο)}RuCl] (35), the 16-electron true catalyst [{η6-p-cymene}{η2-N,O-(9ο1-) }Ru] (36), and the hydride [{η6-p-cymene}{η2-N,O-(9ο)}RuH] (37) involved in the reduction process have been isolated, characterized by NMR and ESI-MS, as well as by X-ray crystallography in the case of 35, and their reactivities have been investigated. The results reveal two general trends regarding this catalytic process: (1) the apparent reaction rate and the enantioselectivity are largely controlled by the nature of the amine functionality of the chiral ligand and the arene ring of the RuII precursor; (2) side reactions occur between the ketone substrate and the active catalytic species that affect the concentration of the latter and consequently the apparent rate; the formation of inactive (β-diketonato)RuII complexes is demonstrated in the case of β-oxo esters.

Oxygen atom transfer from a chiral oxaziridinium salt. Asymmetric epoxidation of unfunctionalized olefins

The synthesis of an optically pure oxaziridinium salt from (1S,2R)-(+)- norephedrine and the study of the asymmetric oxygen transfer reactions from this reagent to unfunctionalized olefins are described.

N-Benzyl-norephedrine derivatives as new, efficient ligands for ruthenium-catalyzed asymmetric transfer hydrogenation of functionalized ketones

Significant catalytic activities (up to 600 h-1 at 20°C) and enantiomeric excesses ranging from 56 to 89% for the asymmetric transfer hydrogenation of β-ketoesters, methoxyacetone and 2-acetylpyridine to the corresponding alcohols are achieved in the presence of catalytic combinations of [RuCl2(η6-arene)]2 and N-substituted derivatives of (1S,2R)- norephedrine such as N-benzyl-norephedrine and N-(4-biphenyl)methyl- norephedrine.

Bicyclic and tricyclic compounds with β-amino alcohol groups as chiral ligands in the enantioselective reaction of diethylzinc with aldehydes

Reduction of the enantiomerically pure allyloxy esters 9 or ent-9 with DIBAH afforded the corresponding aldehydes which were treated in situ with chiral or achiral hydroxylamines 8 to give nitrones 10. These underwent a spontaneous intramolecular 1,3-dipolar cycloaddition, affording the bicyclic compounds 11 and 12, respectively. In an analogous manner, a mixture of the tricyclic compounds 14 and 15 was prepared. Treatment of compound 16 with cyclohexene oxide afforded a mixture of diastereomers 17 and 18. Diastereomers 14 and 15 as well as 17 and 18 could be separated by chromatography. X-ray analyses of compounds 11Ff, 17, and 11Af · HCI were performed. The bicyclic and tricyclic compounds were used as chiral ligands in the reaction of diethylzinc with aldehydes 19, in particular with benzaldehyde (19a). Using bicyclic compounds with a tertiary β-hydroxyalkyl substituent at the N atom as ligands, ee's in the range of 78 to 95% were found. Whereas for the best ligands 11Ae and Af the enantioselectivity in the reaction of 4-tolualdehyde was only slightly decreased, with the aliphatic aldehydes 19c and d distinctly lower enantioselectivities were determined. VCH Verlagsgesellschaft mbH, 1997.

Selective O-benzylation of aminoalkanols

A simple and one-step method has been developed for selective O-benzylation of aminoalkanols. Study of steric effects shows the best selectivity in adjacent 1°-OH vs 2°-CHNH2 and decreased selectivity in 2°-OH vs 1°-CH2NH2 and non adjacent aminoalkanol.

The Stereospecific Synthesis of a New Chiral Oxaziridinium Salt.

A new chiral oxaziridinium salt has been prepared from (1S,2R)-(+)-norephedrine.Enantioselective oxygen transfers to prochiral olefins and sulfides may be performed either stoichiometrically or in a catalytic cycle.