TY - JOUR
T1 - Syntheses and Catalytic Hydrogenation Performance of Cationic Bis(phosphine) Cobalt(I) Diene and Arene Compounds
AU - Zhong, Hongyu
AU - Friedfeld, Max R.
AU - Chirik, Paul J.
N1 - Publisher Copyright:
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Chloride abstraction from [(R,R)-(iPrDuPhos)Co(μ-Cl)]2 with NaBArF4 (BArF4=B[(3,5-(CF3)2)C6H3]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)-(iPrDuPhos)Co(η2,η2-diene)][BArF4]. 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)-(iPrDuPhos)Co(diene)][BArF4] derivatives, proved to be highly active and enantioselective precatalysts for asymmetric alkene hydrogenation. A cobalt–substrate complex, [(R,R)-(iPrDuPhos)Co(MAA)][BArF4] (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.
AB - Chloride abstraction from [(R,R)-(iPrDuPhos)Co(μ-Cl)]2 with NaBArF4 (BArF4=B[(3,5-(CF3)2)C6H3]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)-(iPrDuPhos)Co(η2,η2-diene)][BArF4]. 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)-(iPrDuPhos)Co(diene)][BArF4] derivatives, proved to be highly active and enantioselective precatalysts for asymmetric alkene hydrogenation. A cobalt–substrate complex, [(R,R)-(iPrDuPhos)Co(MAA)][BArF4] (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.
KW - alkene hydrogenation
KW - asymmetric catalysis
KW - catalyst–substrate complex
KW - cobalt
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U2 - 10.1002/anie.201903766
DO - 10.1002/anie.201903766
M3 - Article
C2 - 31071227
AN - SCOPUS:85068793106
SN - 1433-7851
VL - 58
SP - 9194
EP - 9198
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 27
ER -