Borate Esters: Simple Catalysts for the Sustainable Synthesis of Complex Amides
Tom Sheppard describes the use of borate esters as catalysts for the sustainable synthesis of a variety of complex amides.
Direct amidation is an extremely important transformation in organic chemistry that is widely used by researchers throughout academia and industry, perhaps most significantly in the pharmaceutical industry. As a consequence of the inefficient stoichiometric methods that are used to achieve direct amidation reactions, there has been a renewed interest in the past 10–20 years in the development of catalysts for the reaction.
Catalytic approaches using boron-based systems or group IV metals have been particularly successful, but as yet these reactions suffer from significant drawbacks with high dilution conditions and large quantities of molecular sieves being required for efficient water removal. Previously, the group of Professor Tom Sheppard at University College London (UK) developed the use of commercially available B(OCH2CF3)3 as a stoichiometric reagent for direct amidation. Now, they present a catalytic amidation system based on B(OCH2CF3)3 with remarkably higher reactivity than the group’s previous stoichiometric amidation method, with an unprecedented substrate scope.
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