20080-12-0

Upstream product

• 856680-05-2 E-(3R)-(+)-1,3-diphenyl-3-phenylsulfanylpropan-1-one oxime 
• 74-88-4 methyl iodide 
• 614-47-1 1,3-diphenyl-propen-3-one 
• 4894-23-9 3,5-diphenyl-4,5-dihydro-isoxazole 
• 98-88-4 benzoyl chloride 
• 74408-99-4 (3R)-(+)-1,3-diphenyl-3-phenylsulfanylpropan-1-one 
• 873-67-6 benzonitrile oxide 

Downstream Products

• 42052-51-7 (S)-3-hydroxy-1,3-diphenyl-propan-1-one 

Relevant academic research and scientific papers

Chiral differentiation of novel isoxazoline derivatives on clicked thioether and triazole bridged cyclodextrin chiral stationary phases

Isoxazoline derivatives have been disclosed in the art as having acaricidal and insecticidal activity and as potential precursors for the syntheses of natural products. This work first demonstrates the chiral resolution of isoxazoline derivatives that had not been studied before on native cyclodextrin (CD) chiral stationary phases (CSPs). Two structurally well-defined CSPs based on native CD were prepared via different click procedures and applied for the enantioseparation of isoxazolines. Most of the studied isoxazolines were found to be well resolved (Rs > 1.5) under reversed phase mode, especially 4NPh-OPr, which exhibits the best enantioselectivity and resolution (α = 2.22; Rs = 4.16). Optimal resolutions were achieved by evaluating the influences of mobile phase composition, substitution moieties and CSP linkages on the separation. This contribution verifies that excellent enantioseparation of isoxazolines can be accomplished on smartly designed native CD-CSP, which provides a facile and economic way to obtain enantiopure isoxazoline derivatives.

Asymmetric reduction of racemic 2-isoxazolines

The kinetic resolution of racemic 2-isoxazolines was carried out by asymmetric reduction using borane with 1,2-amino alcohols as a chiral source. Using excess BH3-THF in the presence of (-)-norephedrine, optically active 1,3-amino alcohol derivatives were obtained with good ee but in lower yield, while the optically active substrates 2-isoxazolines were recovered with modest ee. The asymmetric reduction using 2.0 equiv of BH3-SMe2 was investigated as an alternative strategy for the synthesis of optically active products. After reduction, treatment of the resulting mixture with Et3N was successful in providing optically active isoxazolidine derivatives in good yields and with good ee. The choice of chiral source was also shown to have a significant effect. In particular, the use of (S)-α,α-diphenyl-2-pyrrolidinemethanol reversed the enantioselectivity of the recovered substrates.

Ring-closure reactions through intramolecular substitution of thiophenoxide by oxygen and nitrogen nucleophiles: Simple stereospecific synthesis of 4,5-dihydroisoxazoles and 4,5-dihydropyrazoles

A new and simple method for the stereospecific synthesis of 3,5-disubstituted-4,5-dihydro-isoxazoles (chiral isoxazolines) from readily available oximes of chiral Michael adducts of thiophenol to chalcones is reported. An analogous reaction with the N-arylhydrazones of the Michael adduct gave nonracemic 1-(aryl)-3,5-diphenyl-4,5-dihydro-1H-pyrazoles (chiral pyrazolines), but these products are configurationally unstable. The key step of the synthesis is the ring-closure reaction, which occurs by a stereospecific intramoleculer nucleophilic substitution of thiophenoxide.

Enhanced asymmetric induction in cycloadditions to bridgehead-chiral vinyl dioxazaborocines

Vinyl dioxazaborocines 5 with asymmetric centres on the nitrogen bridgehead substituent have been prepared and assayed in nitrile oxide and nitrone cycloadditions, giving asymmetric inductions of up to 70 and 74% ee, respectively. (C) 2000 Elsevier Science Ltd.