Hydrogenation of 9-pyridylmethylene- and 9-benzylidene(aza)fluorenes in the presence of rhenium heptasulfide

Hydrogenation of 9-pyridylmethylene(aza)fluorenes and 9-benzylidene-4-azafluorene at 250°C and pH2 = 130 atm in the presence of Re2S7 as a catalyst occurs preferably at the exocyclic double bond of the fulvene fragment to yield pyridyl-9-(aza)fluorenylmethanes. © 1996 Plenum Publishing Corporation.