LAUSR

Organoboron reagents are important synthetic intermediates that play a key role in the construction of natural products, pharmaceuticals, and organic materials.1 The discovery of simpler, milder and more efficient approaches to organoborons opens a route to diverse substances.2-5 Here we show a general method of directed C-H activation for site-selective C-H borylation of arenes and heteroarenes avoiding the use of metal catalysts. C7 and C4-borylated indoles are produced by a mild approach with broad functional group compatibility. The mechanism involves BBr3 as both reagent and catalyst and is established with DFT calculations. Downstream transformation of the formed boron species to natural products and drug scaffolds highlights the potential utility of this strategy.