Ruthenium-Catalyzed Cyclization of Diols to Lactones
J. Zhao, J. F. Hartwig*
Yale University, New Haven, USA
23 September 2005 (online)
γ-Butyrolactone is prepared in quantitative yield by the dehydration of 1,4-butanediol using various ruthenium complexes without the need of hydrogen acceptors or solvent. An alkylphosphine analogue of Noyori’s bis-phosphine diamine catalysts was found to exhibit very high TON (17.000). Several other Ru complexes [RuH2(PMe3)4 and RuH2(CO)(PMe3)3] also provided good yields of products.