Regioselective β-Azidoselenoalkylation of Indoles, Azaindoles, and 7-Deazapurines via a Two-Step, One-Pot Protocol.

Herein, we report the synthesis of β-azidoselenoalkylation of indoles, azaindoles, and deazapurines via a one-pot reaction involving two sequential steps─regioselective addition of the selenocyanate to heterocycles such as indole, azaindole, and 7-deazapurine using KSeCN, followed by the incorporation of the azidoalkyl group from styrenes and sodium azide. The two steps are mediated by two different oxidants, which have been optimized. The overall reaction proceeds via addition of the selenocyanate radical to the heterocycle, followed by homolytic cleavage of the SeCN to generate a heteroaryl-seleno radical that adds to the styrene to generate a benzylic radical and is followed by a radical-polar crossover and subsequent nucleophilic addition of the azide ion to form the product.