Levoglucosenone (LGO), a valuable chiral platform chemical that can be efficiently produced from catalytic fast pyrolysis of cellulose, has been efficiently converted into optically pure (S)-γ-hydroxymethyl-α,β-butenolide (HBO) using a two-step sequence involving a lipase-mediated Baeyer–Villiger oxidation and an acid hydrolysis. In the same fashion, (S)-γ-hydroxymethyl-γ-butyrolactone (2H-HBO) was successfully obtained through a three-step sequence (Baeyer–Villiger, palladium-catalysed hydrogenation and acid hydrolysis). The use of solid buffers in the lipase-mediated Baeyer–Villiger oxidation has proved beneficial in two ways: not only the reaction time and the enzymatic load were both reduced four-fold (from 8 to 2 hours and 464 to 113 U mmol⁻¹) to reach conversions ≥83%, but solid buffers also prevented lipase from denaturation, thus preserving its enzymatic activity and allowing its use for further oxidation cycles.

In 2021, Hawaii will permanently ban the use and sale of octinoxate-based sunscreens as studies have shown serious impacts of such UV filters on the coral reef. This ban, which could be generalized to other countries, highlights the extreme need to offer alternative UV filters that are not only effective in terms of sun protection, but also healthy with regards to human health and the environment. In this context, a wide library of p-hydroxycinnamic esters deriving from naturally occurring sinapic acid has been synthesized using a Knoevenagel–Doebner condensation. The UV filtering activities as well as the antioxidant properties of these sinapic acid esters were then investigated. The results showed promising UVB protection and antioxidant efficacy. A Structure–Activity Relationship (SAR) study on the sinapic acid esters highlighted the need of a free phenol to, as expected, observe antioxidant activity, but also to obtain a higher intensity of protection. Moreover, the nature of the ester moiety also proved to be a key structural feature for the UV absorbance, as higher steric hindrance on the ester moiety leads to more active compounds. The judicious structural design of sinapic esters thus provides promising compounds combining UV protection and antioxidant activity.

p-Hydroxycinnamic diacids are reaction intermediates of the classical Knoevenagel–Doebner condensation between malonic acid and benzaldehydes. As they are generally obtained in low yields, they remain relatively under-studied and under-exploited. Herein, we developed and optimized a sustainable synthetic procedure allowing the production of these compounds in good to high yields (60–80%) using proline as the catalyst and ethanol as the solvent. Study of their antioxidant and anti-UV activities revealed that these p-hydroxycinnamic diacids were not only potent radical scavengers but also efficient UV filters exhibiting high photostability.

Lignocellulose-derived p-hydroxycinnamic acids possess the photo-responsive reversible α,β-unsaturated ester moiety, a reactive structural feature that functions as the basis of the photo-reversible [2 + 2] cycloaddition reaction. To explore the potential of these naturally occurring compounds in the field of self-healing materials, novel bio-based photo-crosslinkable lignin- and glycerol-derived polyfunctional monomers having cinnamate groups were produced using a sustainable process from vanillin and syringaldehyde, two compounds readily obtained from the oxidation of lignin. Through a Structure–Activity Relationship (SAR) study, the structural design of these bio-based monomers was optimized with regards to the crosslinking/decrosslinking extent and the self-healing capacity of the corresponding polymer material. The lignin- and glycerol-derived tri-functional monomer with 4-O-propyl-ferulate moieties has facilitated the design of a new family of bio-based, environment-friendly and reversible self-healing materials for widespread applications. Computational density-functional theory (DFT) and time-dependent DFT calculations were further used for the verification of the SAR study in terms of dimerization energy of the synthesized monomers.

Faced with the ban of some organic UV filters such as octinoxate or avobenzone, especially in Hawaii, it became essential to offer new alternatives that are both renewable and safe for humans and the environment. In this context, a class of bio-based molecules displaying interesting UV filter properties and great (photo)stability has been developed from Meldrum’s acid and bio-based and synthetic p-hydroxycinnamic acids, furans and pyrroles. Moreover, p-hydroxycinnamic acid-based Meldrum’s derivatives possess valuable secondary activities sought by the cosmetic industry such as antioxidant and anti-tyrosinase properties. The evaluation of the properties of mixture of judiciously chosen Meldrum’s acid derivatives highlighted the possibility to modulate secondary activity while maintaining excellent UV protection. Meldrum’s acid derivatives are not only competitive when benchmarked against organic filters currently on the market (i.e., avobenzone), but they also do not exhibit any endocrine disruption activity.