The development of green solvents is one of the key tenets of Green Chemistry as solvents account for the majority of waste stemming from the production of the chemicals on which we have all come to rely. An important class of solvents is the dipolar aprotics, which include N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP). In addition to being derived from non-renewable resources, these solvents are also under increased regulatory pressures that will limit their industrial applications. This Concept concerns the bio-available solvent Cyrene (dihydrolevoglucosenone) as a potential replacement for toxic dipolar aprotic solvents. An emphasis is placed on examining the strengths and weaknesses of Cyrene as a solvent and is accomplished by looking at the synthesis, derivatization, and application in synthetic protocols of Cyrene. With respect to the Twelve Principles of Green Chemistry, this Concept describes a bio-available solvent that should have a disruptive effect on the use of traditional industrial dipolar aprotic solvents.

Palladium nanoparticles (PdNPs) supported on cellulose nanocrystals (CNXL) were synthesized in a single step from Pd­(hexafluoroacetylacetonate)2 (Pd­(hfac)2) in subcritical and supercritical carbon dioxide. CNXLs acted as both the reducing agent and support material for the obtained nanoparticles. Dry Pd nanoparticles supported on the cellulose nanocrystals (PdNP@CNXL) were obtained by simply venting the CO2 and were characterized by FT-IR, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The results show that the Pd nanoparticle diameters varied between 6 and 13 nm with varying pressure (240–2200 psi), reaction time (2–17 h), and weight ratio of the precursor Pd­(hfac)2 to CNXL (1–4% w/w). Particles with diameters above 13 nm appeared not to remain attached to the CNXL surface. Reaction conditions also affected the Pd loading in the final PdNP@CNXL composite. Finally, the PdNP@CNXL composites were shown to be effective catalysts for carbon–carbon bond formation in the Mizoroki–Heck cross-coupling reaction, in line with other reports.

-Cyrene as a bio-alternative solvent: a highly efficient, waste minimizing protocol for the synthesis of ureas from isocyanates and secondary amines in the bio-available solvent Cyrene is reported. This method eliminated the use of toxic solvents, such as DMF, and established a simple work-up procedure for removal of the Cyrene, which led to a 28-fold increase in molar efficiency versus industrial standard protocols.

Auto‐tandem catalysis (ATC) is a powerful method for the synthesis of heterocycles and carbocycles as well as acyclic compounds. The process is defined as a single reagent catalysing multiple, mechanistically distinct processes of a chemical reaction. In this review recent advances in ATC using transition metal catalysts is described. In particular, the use of different catalytic systems for the controlled synthesis of the desired product, enantioselective synthesises in which multiple bonds are formed and mechanistic investigations are illustrated with applications to the synthesis of heterocycles and carbocycles as well as acyclic compounds. New approaches that use earth abundant catalysts, greener solvents or increased catalyst efficiency are highlighted. Examples of ATC reaction development are also included. In addition, ATC processes are used as key steps in the synthesis of natural products as well as biologically active compounds.