1381840-93-2Relevant academic research and scientific papers
Formal insertion of o-carborynes into ferrocenyl C-H bonds: A simple access to o-carboranylferrocenes
Wang, Sunewang Rixin,Xie, Zuowei
, p. 4544 - 4550 (2012)
Insertion of o-carborynes (1,2-dehydro-o-carboranes) into ferrocenyl C-H bonds has been described, providing a convenient methodology for the preparation of functionalized ferrocenyl o-carboranes. Reaction of the carboryne precursors 1-I-2-Li-9,12-Me2-1,2-C2B10H8 or 1-I-2-Li-3-R-1,2-C2B10H9 (R = H, Ph, Me, Cl, Br, and I) with 2.5 equiv of ferrocene at 80 °C in cyclohexane afforded [1-(η5-C5H4)(9,12-Me2-1,2-C 2B10H9)]Fe(η5-C 5H5) and [1-(η5-C5H 4)(3-R-1,2-C2B10H10)] Fe(η5-C5H5) (R = H, Ph, Me, Cl, Br, and I) in 19-44% isolated yields. On the other hand, in addition to the desired C-H bond insertion products [1-(η5-C5H4)(3-X-1, 2-C2B10H10)]Fe(η5-C 5H5), bis(ferrocenyl)-o-carboranes 1,2- [(η5-C5H5)Fe(η5-C 5H4)]2-3-X-1,2-C2B 10H9 were isolated from the reactions of 1-I-2-Li-3-X-1,2-C2B10H9 (X = Cl, Br, and I) in 12%, 15%, and 8% yields, respectively. Treatment of 1,2-dilithio-o-carborane or 1-lithio-2-methyl-o-carborane with ferrocenium hexafluorophosphate in cyclohexane also generated [1-(η5-C5H 4)(1,2-C2B10H11)] Fe(η5-C5H5) and [1-(η5- C5H4)(2-Me-1,2-C2B10H 10)]Fe(η5-C5H5) in 17% and 31% isolated yields, respectively. On the basis of these observations, it is suggested that the single-electron oxidation of ferrocene to the electrophilic ferrocenium cation by o-carborynes is crucial for the insertion reaction. Accordingly, a reaction mechanism is proposed.
