Syntheses and Catalytic Hydrogenation Performance of Cationic Bis(phosphine) Cobalt(I) Diene and Arene Compounds.

Autor: Zhong H; Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, NJ, 08544, USA., Friedfeld MR; Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, NJ, 08544, USA., Chirik PJ; Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, NJ, 08544, USA.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2019 Jul 01; Vol. 58 (27), pp. 9194-9198. Date of Electronic Publication: 2019 May 27.
DOI: 10.1002/anie.201903766
Abstrakt: Chloride abstraction from [(R,R)-( iPr DuPhos)Co(μ-Cl)] 2 with NaBAr F 4 (BAr F 4 =B[(3,5-(CF 3 ) 2 )C 6 H 3 ] 4 ) in the presence of dienes, such as 1,5-cyclooctadiene (COD) or norbornadiene (NBD), yielded long sought-after cationic bis(phosphine) cobalt complexes, [(R,R)-( iPr DuPhos)Co(η 2 ,η 2 -diene)][BAr F 4 ]. The COD complex proved substitutionally labile undergoing diene substitution with tetrahydrofuran, NBD, or arenes. The resulting 18-electron, cationic cobalt(I) arene complexes, as well as the [(R,R)-( iPr DuPhos)Co(diene)][BAr F 4 ] derivatives, proved to be highly active and enantioselective precatalysts for asymmetric alkene hydrogenation. A cobalt-substrate complex, [(R,R)-( iPr DuPhos)Co(MAA)][BAr F 4 ] (MAA=methyl 2-acetamidoacrylate) was crystallographically characterized as the opposite diastereomer to that expected for productive hydrogenation demonstrating a Curtin-Hammett kinetic regime similar to rhodium catalysis.
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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