ABSTRACT
As biochemical entities, glycosyl phosphates are ubiquitous in all living organisms. In particular, glycosyl-1-phosphates are of paramount importance since they are the direct precursors of nucleotide sugars, the substrates of the so-called Leloir enzymes.1 Therefore, the stereoselective phosphorylation of carbohydrate at the anomeric position has naturally been a topic of intense research aiming at the preparation of enzyme’s substrates or at the synthesis of analogues of natural metabolites.2 The α-and β-stereoselective phosphorylations of manno-structures have been particularly studied due to their biochemical relevance in natural products,3 including GDP-α-mannose,1 the substrate of mannosyl transferases and β-d-manno-heptose 1-phosphate, a very important bacterial glycoside.4 Indeed, the latter is the biosynthetic precursor of heptosides found in the lipopolysaccharide, a key component of the outer membrane of Gram-negative bacteria.
