Applications of potassium-graphite and metals dispersed on graphite in organic synthesis

Abstract

Potassium-graphite (C8K), easily prepared by melting potassium over graphite at 150-200 °C under argon, has been used as heterogeneous reagent in several reactions, including the Birch-type reaction of α,β-unsaturated ketones and carboxylic acids and of Schiffs bases, the reductive cleavage of vinylic and allylic sulfones, the selective alkylation of aliphatic esters, imines and nitriles, and the reductive decyanation of nitriles. Potassium-graphite has also been exploited to prepare active metals, highly dispersed on the graphite surface (Met-Gr), by the reaction with the corresponding metal halides in ethereal solvents. The active metals prepared have found applications in Reformatsky reactions (Zn-Gr), preparations of allylic organometallic species (Zn-Gr, Sn-Gr), reductive coupling of carbonyl compounds (Ti-Gr), debromination (Fe-Gr), vinylic and allylic substitution (Pd-Gr), and hydrogenation reactions (Pd-Gr, Ni-Gr). © 1985 IUPAC