Timothy Clark, from the University of San Diego, will deliver a seminar entitled, "Amine- and Phosphine-Directed C–H Borylation: From Catalyst Development to Synthetic Utility." Hosted by Keith Woerpel.
For more information about Tim Clark, click here.
Abstract: Selective C–H bond functionalization of arenes continues to be an important avenue of research as a method to efficiently synthesize biologically relevant, substituted arenes from simple precursors. Conversion of unreactive C–H bonds to synthetically useful C–B bonds allows for production of value-added fine chemicals based on the versatility of the C–B bond in synthesis. Iridium-catalyzed, amine-directed arene C–H borylation reactions were pursued by replacing the commonly used di-tert-butylbipyridine ligand with a hemi-labile bidentate ligand. A summary of the mechanistic study of this reaction and synthetic transformations of the products will be discussed. These ligand effects have been used to expand the scope of directing groups that can be used to obtain ortho-borylation. In particular, phosphines have been shown to be effective substrates, providing ambiphilic phosphine boronate esters efficiently. The reactive C–B bond can be used to install new functional groups in valuable phosphines, or as a Lewis acid for a bifunctional ligand or organocatalyst.