53665-20-6Relevant academic research and scientific papers
Application of chiral ligands: Carbohydrates, nucleoside-lanthanides and other Lewis acid complexes to control regio- and stereoselectivity of the dipolar cycloaddition reactions of nitrile oxides and esters
Gucma, Miroslaw,Golbiewski, W. Marek,Krawczyk, Maria
, p. 13112 - 13124 (2015)
Chiral Lewis acid mediated 1,3-dipolar cycloaddition reactions of 4-trifluoromethylbenzonitrile oxide to methyl crotonate as well to β-substituted acrylates and (Z)-pent-2-en-1-yl esters were examined. Excellent enantioselectivities with moderate to good regioselectivities were achieved for crotonates with complexes of BiBr3 with (+)-(4,6-benzylidene)methyl-α-d-glucopyranoside C, with the l-ascorbic acid I-FeCl3 system, and with lipase Candida antarctica. High enantiomeric excess was observed for isopropyl ester and benzyl ester. The outstanding ee values were achieved for acrylates with β-t-butyl, cyclohexyl, and 1,3-benzodioxol-5-yl groups in cycloadditions catalyzed by C-Yb(OTf)3 and the (+)-2-hydroxy-3-pinanone N-TiCl4 system. High enantioselectivities were found in reactions of (Z)-pent-2-en-1-yl esters mediated by complexes N-Mg(OTf)2 and N-TiCl4.
