| Abstract
| - Dihydrogen can be activated by lithium and potassium organoamides,particularly thediisopropyl and bis(trimethylsilyl) derivatives, to reducearomatic compounds at 1000 psig and200 °C. Naphthalene was hydrogenated to tetralin in 100% yieldby both reagents; anthracenewas reduced with the bis(trimethylsilyl)amide catalyst to amixture of the correspondingmonocyclic aromatic derivatives,1,2,3,4,4a,9,10,10a-octahydroanthracene (15%) and1,2,3,4,5,6,7,8-octahydroanthracene (84%); phenanthrene was reduced with this base to amixture of 1,2,3,4,5,6,7,8-octahydrophenanthrene (63%),1,2,3,4,4a,9,10,10a-octahydrophenanthrene (33%), and1,2,3,4-tetrahydrophenanthrene (4%); chrysene was converted by the same reagentto 1,2,2a,3,4,5,6,6a,9,10,11,12-dodecahydrochrysene (70%) and1,2,2a,3,4,5,6,6a-octahydrochrysene (25%); and1,2-benzanthracene was hydrogenated to a mixture of dihydro- anddodecahydro-1,2-benzanthracenes.The reaction products show a striking selectivity for thepreservation of an interior benzene ring.The catalytic properties of the strong bases depend on the natureof the organic ligands in thedialkylamide and the corresponding metal cations. The reactionsproceed at modest pressures,about 500 psig, but require high temperatures, about 200 °C. Theproducts of the reaction withdideuterium were investigated by magnetic resonance spectroscopy todefine the reaction pathway.The results of these experiments and other available informationsuggest that hydrogen istransferred from an anionic dihydrogen−dialkylamide complex to thearomatic compound in theslow step of the reaction.
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