C-2 epimerization of aldoses promoted by combinations of metals and diamines involving a novel rearrangement of the carbon skeleton
Abstract
Aldoses are epimerized at C-2 by combinations of certain metals (Ni2+, Co2+, Ca2+, and Sr2+) and diamines (N,N,N′-trimethylethylenediamine and N,N,N′,N′-tetramethylethylenediamine), and a 13C n.m.r. study reveals that a novel rearrangement of the carbon skeleton, the exchange of C-1 and C-2 atoms by inversion of the C-1–C-2 aldose fragment, is involved in this reaction.