The twelve principles of Green Chemistry. Chemistry metrics. Solvents in organic synthesis: life cycle and solvent parameters. Solventless reactions. Alternative solvents: water; biphasic systems; fluorinated liquids; supercritical fluids; supercritical CO2 and CXL; ionic liquids (RTILs and DES); solvents from renewable resources. Concept of catalyst. Catalysis by solid acids and bases. Catalyzed reductions and oxidations: the use of H2 and O2. Catalyzed C-C bond formations and building blocks with high atom economy. Asymmetric synthesis and organocatalysis. Shape selective catalysis: zeolites and cyclodextrins. Biocatalysis. Microfluidics. Photochemistry. Mechanochemistry, microwave and sonochemistry. Chemicals from renewable sources.