Regioselective Mono- and Dialkylation of [6,6]-open C 60 (CF 2 ): Synthetic and Kinetic Aspects.

Autor: Bogdanov VP; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia.; Endocrinology Research Centre, 12 Dm.Ul'yanova, str., 117036, Moscow, Russia., Brotsman VA; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia., Belov NM; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia., Rybalchenko AV; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia., Markov VY; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia., Troyanov SI; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia., Goryunkov AA; Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia.
Jazyk: angličtina
Zdroj: Chemistry, an Asian journal [Chem Asian J] 2020 Jun 02; Vol. 15 (11), pp. 1701-1708. Date of Electronic Publication: 2020 Apr 30.
DOI: 10.1002/asia.202000320
Abstrakt: Alkylation of homofullerene [6,6]-C 60 (CF 2 ) 2- dianion with the set of alkyl halides, RX, was established to demonstrate an effect of RX nature on the conversion, product composition, and regioselectivity. The respective C 60 (CF 2 )RH, C 60 (CF 2 )R 2 and C 60 (CF 2 )R'R'' compounds were obtained in the reaction with sterically unhindered RX, isolated by HPLC and unequivocally characterized. The kinetic studies evidenced S N 2 mechanism for both alkylation steps, yielding mono- and dialkylated C 60 (CF 2 ), respectively, and indicated the negative charge localization at the bridgehead carbon atoms as well as a steric hindrance of the CF 2 moiety likely to be a key factors for the S N 2 reaction mechanism and observed regioselectivity. The significant difference in the rate constants of the first and the second steps is attributed to the different activation barriers predicted by DFT calculations which makes possible to develop synthetic methods for the regioselective preparation of monoalkylated C 60 (CF 2 )RH and heterodialkylated C 60 (CF 2 )R'R'' derivatives.
(© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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