1058-08-8Relevant articles and documents
THIENYL AND PERFLUOROPHENYL DERIVATIVES OF DIVALENT LANTHANIDES
Syutkina, O. P.,Rybakova, L.F.,Petrov, E. S.,Beletskaya, I. P.
, p. C67 - C69 (1985)
The reflection of oxidative addition of α-iodothiophene and bromopentafluorobenzene to zero-valent lanthanides has been carried out.The formation of organolanthanide derivatives RLnX (R0α-C4H3S, C6F5) has been confirmed by isolation of the corresponding R
Carbon-hydrogen bond stannylation and alkylation catalyzed by nitrogen-donor-supported nickel complexes: Intermediates with Ni-Sn bonds and catalytic carbostannylation of ethylene with organostannanes
Doster, Meghan E.,Johnson, Samuel A.
, p. 4174 - 4184 (2013/09/02)
The reaction of H2C=CHSnR3 with C6F 5H, where R = Bu, Bn, Ph, was catalyzed by Ni(COD)2 and the nitrogen donor ancillary ligand MeNC5H4N iPr. These reactions produced the stannylation products C 6F5SnR3 (1R) and C-H alkylation products C6F5CH2CH2SnR3 (3R). The Bu substituent provided the best selectivity for stannylation, whereas the Ph substituent provided primarily the alkylation product. The catalytic intermediate (MeNC5H4N iPr)Ni(η2-H2C=CHSnR3) 2 (2R) was observed by NMR spectroscopy and isolated in the case of R = Ph. A second catalytic intermediate, cis-(MeNC5H 4NiPr)2Ni(C6F5)(SnR 3) (4R), was observed by NMR spectroscopy and isolated for R = Bn, Ph by the reaction of C6F5SnR3 with MeNC5H4NiPr and Ni(COD)2. The reaction of C6F5SnR3 with ethylene in the presence of catalytic MeNC5H4NiPr and Ni(COD)2 provided the carbostannylation product 3R. Mechanistic studies of the C-H stannylation/alkylation mechanism were performed to propose a mechanistic manifold for these transformations.
A mechanistic investigation of carbon-hydrogen bond stannylation: Synthesis and characterization of nickel catalysts
Johnson, Samuel A.,Doster, Meghan E.,Matthews, Jacob,Shoshani, Manar,Thibodeau, Michelle,Labadie, Amanda,Hatnean, Jillian A.
, p. 8135 - 8143 (2012/08/08)
The complex (iPr3P)Ni(η2-Bu 3SnCHCH2)2 (1a) was characterized by NMR spectroscopy and was identified as the active species for catalytic C-H bond stannylation of partially fluorinated aromatics, for example in the reaction between pentafluorobenzene and Bu3SnCHCH2, which generates C6F5SnBu3 and ethylene. The crystalline complex (iPr3P)Ni(η2-Ph 3SnCHCH2)2 (1b) provides a more easily handled analogue, and is also capable of catalytic stannylation with added Ph 3SnCHCH2 and C6F5H. Mechanistic studies on 1b show that the catalytically active species remains mononuclear. The rate of catalytic stannylation is proportional to [C6F 5H] and inversely proportional to [Ph3SnCHCH2]. This is consistent with a mechanism where reversible Ph3SnCHCH 2 dissociation provides (iPr3P) Ni(η2-Ph3SnCHCH2), followed by a rate-determining reaction with C6F5H to generate the stannylation products. Kinetic competition reactions between the fluorinated aromatics pentafluorobenzene, 1,2,4,5-tetrafluorobenzene, 1,2,3,5- tetrafluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene and 1,3-difluorobenzene all suggest significant Ni-aryl bond formation in the rate-determining step under catalytic conditions. Labelling studies are consistent with an insertion of the hydrogen of the arene into the vinyl group, followed by β-elimination or β-abstraction of the SnPh3 moiety.
