The metal-catalyzed functionalization of unactivated alkane C–H bonds remains a significant challenge that could provide new approaches to a range of synthetic targets. The borylation of sp3-hybridized C–H bonds is one area that has great potential based on the diverse reactions of carbon–boron bonds. Such reactions have been limited outside of the functionalization of primary, unfunctionalized alkanes or benzylic C–H bonds. One notable exception was reported by Sawamura and co-workers in 2012, in which they used silica-supported phosphine ligands to mediate the amide-directed functionalization of C–H bonds alpha-to nitrogen. Under these conditions, some examples of secondary C–H borylation were also reported. Based on the work by Sawamura, the amide-directed C–H borylation of sp3-hybridized C–H bonds was examined using readily available catalyst systems. Using [(COD)Ir(OMe)]2 as the pre-catalyst in conjunction with an XL-type ligand reported by Smith and Maleczka, 8-(diisopropylsilyl)quinoline was found to afford the desired C–H borylation reaction. The reaction selectivity, scope, and proposed mechanism will be presented. These results will be compared to those obtained with Sawamura’s solid-supported catalyst system.

Amide-directed alkane C-H borylation reactions

254th National Meeting (2017)

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