- 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
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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.
- Doster, Meghan E.,Johnson, Samuel A.
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p. 4174 - 4184
(2013/09/02)
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- Preparation, reactivities, and NMR spectra of pentafluorophenyltin derivatives
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A variety of pentafluorophenyltin compounds were prepared and their chemical properties were examined. These compounds effectively catalyzed Mukaiyama-aldol reaction of ketene silyl acetal in sharp contrast to the inertness of normal alkyltin halides like Bu2SnCl2. The increased Lewis acidity of the pentafluorophenyltin halides was proved by 119Sn- and 13C-NMR spectra. On the other hand, the pentafluorophenyl group reduced the reactivities of tin towards both nucleophiles and electrophiles. 19F-NMR spectroscopy was invoked to elucidate this anomaly.
- Chen, Jian-Xie,Sakamoto, Katsumasa,Orita, Akihiro,Otera, Junzo
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