Isosorbide: functionalization and applications

Isosorbide is a sustainable heterocycle derived from lignocellulosic biomass. Functionalization achieves selectivity through preferential reaction at one of the two chemically non-equivalent hydroxyl groups. Reaction at the isosorbide hydroxyls have resulted in selective formation of acetates, alkyl esters, aryl esters, acrylates, methacrylates, carbamates, and alkyl ethers. Immobilized lipase mediates regioselective esterification and ester cleavage. Functionalization with furoxans provides powerful nitric oxide donors and potential alternatives to the vasodilator drug, isosorbide-5-mononitrate. Substitution, including via Mitsunobu inversions converts isomannide and isoidide to isosorbide derivatives. Iridium-catalysed borrowing hydrogen gives stereoselective amination and α-methyl ketone derivatives. There is a proliferation in the use of isosorbide monomers for radical polymerization, including in reversible addition-fragmentation chain-transfer (RAFT) polymerization. The lack of toxicity and biocompatibility makes isosorbide a scaffold of interest for derivatization in medicinal and polymer chemistry. This review concludes with our perspective on advances in isosorbide chemistry.