Noble Metal versus Abundant Metal Catalysts in Fine Organic Synthesis: Cost Comparison of C-H Activation Methods

There is a common assumption thatreplacement of the classicalcatalyst based on rare and expensive noble metals by the catalystsbased on earth-abundant metals will dramatically reduce the costsof organic synthesis. Herein we demonstrate that it may not be true,mainly because sophisticated organic substrates and modern reagentsare often as expensive as catalytic amounts of noble metals. The particularcost analysis of the syntheses of 3,4-diphenyl-isoquinolone by variousC-H activation methods revealed that the main costs fall onthe stoichiometric reagents rather than the catalysts. As a result,the metal-free synthesis appears to be even more expensive than theprocedures involving ruthenium and rhodium catalysts. Overall, metalprices should not be considered the sole reason for conducting academicresearch without any preliminary analysis.