Studies on the influence of saccharide fragment of urea organocatalysts on the yield and enantioselectivity of aza-Henry reaction

Abstract

Six new bifunctional ureas bearing a carbohydrate ring and an optically active base for the asymmetric aza-Henry reaction of imines with nitromethane has been developed. The influence of the saccharide urea fragment and the base in organocatalysts, both new and previously prepared by our team, on the yield and enantioselectivity of aza-Henry reactions was demonstrated. The aza-Henry reaction products were obtained in 17-98% yield and ee up to 99%. The highly enantioselective reaction course is likely the result of the synergic action of two urea fragments -saccharide and DACH.

Aziridine Ring Opening as Regio- and Stereoselective Access to C-Glycosyl-Aminoethyl Sulfide Derivatives

“…Chiral aziridines are useful intermediates in the synthesis of biologically significant compounds due to their ability to undergo nucleophilic ring opening reactions [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. Considering our previous results on carbohydrate chemistry [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ] and based on our experience in synthesis and catalytic activity in the asymmetric synthesis of chiral aziridines [ 59 , 60 , 61 , 62 , 63 , 64 , 65 ], we decided to couple aziridines to glycals with D-gluco and D-galacto configurations via C -glycosidic bonding, with the final formation of C -glycosyl-aminoethyl sulfide derivatives.…”