Fundamentals of green chemistry: efficiency in reaction design

• Published in: Chemical Society reviews 2012-02, Vol.41 (4), p.1437-1451
• Main Author: Sheldon, Roger A
• Format: Article
• Language: English
• Subjects: Biomass; Catalysis; Enzymes, Immobilized - metabolism; Free Radicals - chemistry; Green Chemistry Technology; Ketones - chemistry; Ketones - metabolism; Nanoparticles - chemistry; Oxidation-Reduction; Solvents - chemistry
• ISSN: 1460-4744
• DOI: 10.1039/c1cs15219j

In this tutorial review, the fundamental concepts underlying the principles of green and sustainable chemistry--atom and step economy and the E factor--are presented, within the general context of efficiency in organic synthesis. The importance of waste minimisation through the widespread application of catalysis in all its forms--homogeneous, heterogeneous, organocatalysis and biocatalysis--is discussed. These general principles are illustrated with simple practical examples, such as alcohol oxidation and carbonylation and the asymmetric reduction of ketones. The latter reaction is exemplified by a three enzyme process for the production of a key intermediate in the synthesis of the cholesterol lowering agent, atorvastatin. The immobilisation of enzymes as cross-linked enzyme aggregates (CLEAs) as a means of optimizing operational performance is presented. The use of immobilised enzymes in catalytic cascade processes is illustrated with a trienzymatic process for the conversion of benzaldehyde to (S)-mandelic acid using a combi-CLEA containing three enzymes. Finally, the transition from fossil-based chemicals manufacture to a more sustainable biomass-based production is discussed.