SUST-CARB - SUstainable and SelecTive conversion of CARBohydrates from Biomass into fine chemicals

The objective of the project (acronym: SUST CARB) is the development of original methodologies for converting two bio-based building blocks (Levoglucosenone (LGO) and Isosorbide (IS)) into complex high added-value fine chemicals. Towards this goal, we will capitalize on synthetic protocols optimized in terms of efficiency (step- and atom-economy, selectivity, operational simplicity) and sustainability (minimization of waste, use of eco-friendly solvents, reagents and conditions). We will adopt complementary types of catalysis (organocatalysis, metal catalysis, biocatalysis and photocatalysis) and smart synthetic protocols (multicomponent and one-pot (telescopic) processes), together with technological improvements (e.g. batch-to-flow mode switch, catalyst immobilization, use of green solvents).

Sugar-like building blocks, like LGO and IS, are considered among the most important commodities of the future, when oil will be gradually replaced by biomass. They derive from the carbohydrate platform, whose main sources (agrifood waste and lignocellulosic materials), are not in competition with food. This project aims at developing original and selective methodologies to convert these two polyfunctionalised bio-based molecules into a variety of useful fine chemicals.

In the first working package (WP), the acetal moiety of LGO will be exploited to undergo original C-C bond formations, leading to novel C-glycosides. Then, the ketone of LGO will be used as such, or after conversion into a primary amine, as substrate for Ugi or Ugi-type multicomponent reactions. Biocatalysis will give an important contribution in the selective handling of the LGO functionalities. Finally, LGO will be converted into a completely new class of biaryls containing a pyrylium betaine.

In WP 2, the selective manipulation of the two diastereomeric hydroxy groups of IS will be thoroughly investigated, with the objective to synthesize conjugates that join two different pharmacophoric groups to the isosorbide central scaffold. Toward this goal we will use several strategies, exploiting organocatalysis, biocatalysis, photocatalysis and multicomponent reactions.

Finally, in WP 3, the above cited methodologies will be made more sustainable. We will transform batch reactions into flow processes, also through catalyst immobilization. Multistep sequence will be converted into one-pot (telescopic) procedures. Oxidation with stoichiometric reagents will be turned into catalytic aerobic methods, and green solvents will be used as much as possible.