Phosphine-directed C–H borylation converts readily available and valuable phosphines into ambiphilic phosphine boronates, utilizing the strong phosphine Lewis base to direct an iridium catalyst to selectively activate an adjacent C–H bond. Our group reported the first example of phosphine-directed C–H borylation in 2014. This talk will focus on a new catalyst developed for this transformation, which involves a cationic iridium pre-catalyst ([(COD)<sub>2</sub>Ir]BF<sub>4</sub>) with 3,4,7,8-tetramethyl-1,10-phenanthroline (TMPHEN) as ligand. This catalyst system has a broad substrate scope that results in a number of phosphine boronate scaffolds. In addition to typical arene C–H borylation, benzylic C–H borylation has been achieved. The scope of substrates amenable to this system will be discussed. Progress in accessing chiral phospine boronates, from chiral phosphines and by asymmetric desymmetrization, will be included.  Finally, early work in functionalizing the C–B bond and using the phosphine boronates as organocatalysts will be described.

Phosphine-directed C–H borylation: accessing ambiphilic phosphine boronates

2019 Spring National Meeting

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