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Structure-activity relationships of Ni particles with different morphologies, crystallinities and compositions were investigated for glucose hydrogenation. Nanorods and nanospheres were obtained respectively by altering hydrogen pressure during synthesis, and nanobead chains were synthesized for analogy analysis following a known procedure. Glucose hydrogenation over Ni nanosphere catalysts exhibits the lowest reaction barrier (Ea = 32 kJ/mol) compared to nanorods and nanobead chains (98 kJ/mol), and a constant sorbitol selectivity of 100 % was obtained at a temperature of 140 °C. A comprehensive characterization with ATR-IR, Raman, XPS, ICP, P-XRD, HRTEM and SAED revealed that the combined factors of poly-crystallinity, amorphous structure and P- dopant make Ni nanospheres superior. This provides a valuable path in the process of designing better non-noble catalysts to definitely avoid the use of noble metals in the future in biomass valorization reactions.

Ni nanoparticles supported on carbon black (Ni/CB) with Ni particle sizes 6.9–23.5 nm were found to exhibit a size effect, with a significant impact on catalytic performance in the glucose hydrogenation reaction. A series of Ni nanoparticles with different sizes, as determined by statistical analysis of TEM images, were obtained by varying the synthesis temperature using a sol-gel method. The highest glucose conversion and sorbitol production in glucose hydrogenation was possible with Ni/CB catalysts with Ni particles size around 17 nm obtained at 550 °C. Similarly, graphene nanoplatelets (GNP) supported Ni with different particle sizes synthesized under different temperature conditions have an identical behaviour, that is, GNP-550 exhibits the highest catalytic performance. Therefore, it can be concluded that size effect appeared when the particle size is above 10 nm, which provides a reference for the design of subsequent catalysts for liquid phase hydrogenation reactions pertinent to biomass conversion.

Carbon black (CB) supported Ni, Fe, or Fe-Ni alloy catalysts were synthesized by sol-gel to elucidate the reaction pathways over each catalyst, as well as synergistic effects in glucose to sorbitol hydrogenation. The bimetallic materials presented small and alloyed nanoparticles that were richer in reduced metallic sites at the surface than their monometallic counterparts. Glucose isomerization to fructose was favoured over Fe/CB, while glucose hydrogenation to sorbitol is the dominating pathway over Ni/CB catalyst. By contrast, sorbitol production was promoted and undesired isomerization was suppressed when Fe and Ni formed a nanoalloy. In addition, the alloy catalyst presented better stability than the corresponding monometallic catalyst. A comparison with a mechanical mixture of Fe/CB and Ni/CB monometallic catalysts demonstrated the synergy at the nanoscale in the alloy. By comparing different Fe:Ni ratios, the 1:1 formulation was identified as the best compromise to achieve a high activity while maintaining high sorbitol selectivity.

Okadaic acid, a potent and selective inhibitor of Protein Phosphatases 1 and 2A (PP1 and PP2A), is widely used as a probe for various biochemical processes. We describe herein two innovative methods for the synthesis of the terminal C28–C38 fragment of the natural polyether. Suárez photochemical oxidative cyclization and electrochemical oxidation of malonates to their ketals equivalents have been successfully applied for the assembly of the key spiroketal core.

A modulable tin based allylation method for the synthesis of 1,2,3-triols is described. The optimization of the reaction was aided by 1H and 119Sn low temperature NMR spectroscopic investigations, which support the formation of two cyclic intermediates after transmetallation. Depending on the nature of the Lewis acid, either syn/anti or anti/syn configured triols could be obtained with good stereocontrol. To demonstrate the value of this methodology and the resulting scaffolds, they were used to install the signature triol motifs of (−)-cleistenolide and of herbarumin I.