Efficient chemoselective hydrogenation of organic azides catalyzed by palladium nanoparticles with alkyne-derived homogeneous supports

Abstract

Catalytic chemoselective hydrogenation of organic azides using palladium nanoparticles stabilized by alkyne derivatives was studied. A broad range of aromatic and aliphatic azides were smoothly reduced to the corresponding amines in excellent yields with a quite small amount of the catalyst. Hydrogenation of 3-phenylpropylazide gave 3-phenylpropylamine almost quantitatively with a substrate-to-palladium molar ratio (S/Pd) of 12,900 under 8atm of H2. The reaction under 1atm of H2 also proceeded smoothly with an S/Pd of 1000. Several reduction-sensitive functional groups, such as carbonyl, halide, benzylic OH, and aliphatic nitro were well tolerated under the reaction conditions.