Synthetic routes and fields of application of isohexides: ubiquitous perspective of relevant industrial compounds

Abstract

Isohexides are a class of compounds that can be obtained from natural sources with simple processes and with interesting properties. Among these, the intrinsic chirality of the rigid bicyclic structural cavity and the presence of two hydroxyl groups in positions 3 and 6 available for functional group interconversion, appeared as the most interesting ones for real innovative applications. In this work, the methods by which isohexides have been synthesized from polysaccharides and biomasses of different complexity have been analyzed. Then, the possible alternatives to the traditional synthetic routes in terms of sustainability and the properties that elect isosorbide as the best candidate for process scalability have been highlighted. In a second moment, the fields of application of these extremely interesting compounds have been investigated as building-blocks, as chiral auxiliaries or as constituents of chiral ionic liquids. Finally, the numerous applicative possibilities of isosorbide as monomer or co-monomer of a wide range of polymeric materials of different nature have been investigated, extending the field of application of isohexidic compounds.