Solvent-Free One-Pot Diversified Protection of Saccharide Polyols Via Regioselective Tritylations

Regioselective installation of trityl protecting groups, widely employed in organic synthesis, was demonstrated to occur in high yields on primary positions of sugar polyols in the presence of a very limited stoichiometric amount of pyridine (ca 2 equivalents) and trityl chloride (1.1 eq) at 100 8C. Under these conditions, that can be regarded as “solvent-free” conditions because of the insolubility of the polyol substrates, reactions take remarkably shorter times than in most examples reported in the literature. In addition, the method proved applicable under air without resorting to inert atmosphere. In the second part of the paper, the scope of the present tritylation approach was significantly extended with the development of streamlined “one-pot” and fully “solvent-free” sequences allowing regioselective tritylation/alkylation (or silylation) of saccharide polyols in short times and good yields, following experimentally simple protocols.