Reversing the Native Aerobic Oxidation Reactivity\nof Graphitic Carbon: Heterogeneous Metal-Free Alkene Hydrogenation

Abstract

Commercially available carbon blacks\nserve as effective metal-free\ncatalysts for the selective hydrogenation of carbon–carbon\nmultiple bonds under aerobic conditions using hydrazine as the terminal\nreductant. The reaction, which proceeds through a putative diimide\nintermediate, displays high tolerance to a variety of functional groups,\nincluding those sensitive to nucleophilic displacement by hydrazine,\naerobic oxidation, or hydrazine-mediated reduction. Hydrazine chemisorbs\nstrongly to the carbon surface, attenuating its native oxidative reactivity\nand allowing for selective hydrogenation. The catalytic sequence established\nhere effectively umpolungs the reactivity of carbon, thereby enabling\nthe use of this low-cost material in selective reduction catalysis.