Olefin metathesis enabled by Schrock-type catalysts : A transformation in the chemical industry
Emmanuel Robé of XiMo discusses advancements in Schrock-type catalysts for metathesis and their role in sustainable chemical production
CM products HCM products
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Metal alkylidene G 1 G2 G 1 G1 G catalyst 2 G2
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Figure 1 - General cross-metathesis & homo cross metathesis reaction
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For the past 60 years , olefin metathesis ( Figure 1 ) has been a game-changer in the field of organic chemistry . Discovered serendipitously by Banks and Bailey at Phillips Petroleum while searching for a catalyst to replace HF acid in high-octane gasoline production , olefin metathesis quickly attracted significant industrial interest .
Its initial applications were in the petrochemical industry , followed by innovations in the rubber industry . Today , thanks to the pioneering work of Nobel laureates like Professor Richard Schrock at MIT and Professor Robert Grubbs at Caltech , olefin metathesis has found applications across various sectors , including pharmaceuticals , materials and speciality chemicals .
Despite these advances , the widespread industrial adoption of olefin metathesis was hindered by challenges such as high costs , complex manufacturing processes , and low catalyst activity . Economically feasible processes require highly selective and active catalysts that enable low catalyst loading and efficient processing . This is where XiMo has made significant progress .
Industrial feasibility & innovation
XiMo , co-founded in 2010 by Nobel laureate MIT Professor Richard Schrock , Boston College Professor Amir Hoveyda , Professor Georg Frater and other industry leaders , has developed highly active and selective Schrock-type catalysts based on molybdenum and tungsten . These catalysts , known for their high activity , have transitioned from a scientific concept to an industrial reality , overcoming previous issues related to sensitivity to oxygen and moisture .
XiMo ’ s catalysts provide a stereochemistry that is not achievable with more commonly used catalysts . They exhibit exceptionally high E- or Z-selectivity , which is crucial for various academic and industrial applications ( Figure 2 ). The specific isomer often solely accounts for biological activity in applications such as pheromones and drug substances . Z-selective and enantioselective ring-closing metathesis ( RCM , Figure 3 ) is vital for synthesising biologically active compounds . For example , the macrocyclic anti-cancer natural
28 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981