Silicon Powder: The First Nonmetal Elemental Catalyst for Aminobromination of Olefins with TsNH₂ and NBS

Silicon powder was found, for the first time, to be an efficient alternative to transition metal catalysts for aminobromination of α,β-unsaturated carbonyl compounds and simple olefins with p-toluenesulfonamide (4-TsNH₂) and NBS, affording the aminobrominated products in high yields and regio- and stereoselectivity. The high reactivity of electron-rich substrates reveals that the reaction has the electrophilic addition feature.