194. “Microwave-Assisted Synthesis and Transformations of Cationic CpRu(II)(naphthalene) and CpRu(II)(naphthoquinone) Complexes”
     E. Bocekova-Gajdošíkova, B. Epik, J. Chou, K. Akiyama, N. Fukui, L. Guénée, E.P. Kündig,
     Helv. Chim. Acta 2019, 102, e190076.

Details of the direct synthesis of cationic Ru(II)(η^5-Cp)(η^6-arene) complexes from ruthenocene using microwave heating are reported. Developed for the important catalyst precursor [Ru(II)(η⁵-Cp)(η⁶-1-4,4a,8a-naphthalene)][PF₆] reaction time could be shortened from three days to 15-min. The method was extended to [Ru(II)(η⁶-benzene)(η⁵-Cp)][PF₆], [Ru(II)(η⁵-Cp)(η⁶-toluene)][PF₆], [Ru(II)(η⁵-Cp)(η⁶-mesitylene)][PF₆], [Ru(II)(η⁵-Cp)(η⁶-hexamethylbenzene)][PF₆], [Ru(II)(η⁵Cp)(η⁶-indane)][PF₆], [Ru(II)(η⁵-Cp)(η⁶-2,6-dimethylnaphthalene)][PF₆], and [Ru(II)(η⁵-Cp)(η⁶-pyrene)][PF₆]. 1-methylnaphthalene and 2,3-dimethylnaphthalene afforded mixtures of regioisomeric complexes. [Ru(Cp)(CH₃CN)₃][PF₆], derived from the naphthalene precursor provided access to the cationic RuCp complexes of naphthoquinone, tetralindione, 1,4-dihydroxynaphthalene, and 1,4-dimethoxynaphthalene. Reduction of the tetralindione complex afforded selectively the endo,endo diol derivative. X-Ray structures of five complexes are reported.

DOI : 10.1002/hlca.201900076 

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