Ambiphilic compounds, possessing both a Lewis acid and Lewis base, have received significant attention in recent years for their ability to serve as organocatalysts in the activation of small molecules and as bifunctional ligands in metal-catalyzed transformations. Phosphine boronates are one class of these ambiphilic compounds that have shown interesting promise in multiple applications. Our group has developed a method for phosphine-directed C–H borylation, providing direct access to a wide variety of phosphine boronates that were not readily accessible previously. The key to the success of this transformation is the use of a cationic iridium catalyst [Ir(COD)<sub>2</sub>]BF<sub>4</sub> with a rigid bidentate ligand 3,4,7,8-tetramethyl-1,10-phenanthroline (TMPHEN). This method works for a wide scope of compounds and gives good yields across a wide range of phosphine scaffolds. Extension of this work to methods that access chiral phosphine boronate esters will be discussed. This includes the phosphine-directed C–H borylation of chiral phosphines and progress toward asymmetric desymmetrization of phosphines, providing P-chiral phosphine boronates. This class of phosphine boronates is initially being sought for their activity as catalysts for Michael additions.

Accessing chiral ambiphilic phosphine boronates by directed C-H borylation reactions

2019 Spring National Meeting

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