STEREOCHEMISTRY OF THE REACTION OF GLUCOPYRANOSYL IMINES WITH PHOSPHITES AND THE MOLECULAR STRUCTURES OF THE PRODUCTS

The stereochemistry of the reaction of N-[p-methyl(or methoxy)benzylidene]-2-amino-2-deoxy-1,3,4,6-tetra-O-acetyl-ß-D-glucopyranose and phosphites is discussed. The configurations of the products are determined by X-ray diffraction analysis. It is found that the content of R-isomers increases as the size of alkyl groups of phosphites increases. This is probably due to the difference of steric hindrance of C 1 -AcO and C 4 -AcO of the glucopyranosyl group to the attack of the phosphite on the imine.