Zhou, Gang, Aboo, Ahmed H, Robertson, Craig M ORCID: 0000-0002-4789-7607, Liu, Ruixia, Li, Zhenhua, Luzyanin, Konstantin ORCID: 0000-0001-9312-7139, Berry, Neil G ORCID: 0000-0003-1928-0738, Chen, Weiping and Xiao, Jianliang ORCID: 0000-0003-2010-247X
(2018)
N,O- vs N,C-Chelation in Half-Sandwich Iridium Complexes: A Dramatic Effect on Enantioselectivity in Asymmetric Transfer Hydrogenation of Ketones.
ACS CATALYSIS, 8 (9).
pp. 8020-8026.
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Abstract
Cyclometalation of [Cp∗IrCl2]2 with methyl (S)-2-phenyl-4,5-dihydrooxazole-4-carboxylate in the presence of NaOAc selectively led to a N,C- or N,O-chelated Cp∗Ir(III) complex, depending on whether or not water was present in the reaction. While derived from the same precursor, these two complexes behaved in a dramatically different manner in asymmetric transfer hydrogenation (ATH) of ketones by formic acid, with the N,O-chelated complex being much more selective and active. The sense of asymmetric induction is also different, with the N,O-complex affording S while the N,C-analogue R alcohols. Further study revealed that the nature of the base additive considerably impacts the enantioselectivity and the effective HCOOH/amine ratios. These observations show the importance of ligand coordination mode and using the right base for ATH reactions.
Item Type: | Article |
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Uncontrolled Keywords: | N,O-chelation, N,C-chelation, half-sandwich iridium complexes, cyclometalation, asymmetric transfer hydrogenation |
Depositing User: | Symplectic Admin |
Date Deposited: | 02 Aug 2018 09:56 |
Last Modified: | 19 Jan 2023 01:29 |
DOI: | 10.1021/acscatal.8b02068 |
Related URLs: | |
URI: | https://livrepository.liverpool.ac.uk/id/eprint/3024497 |
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N,O- vs N,C-Chelation in Half-Sandwich Iridium Complexes: A Dramatic Effect on Enantioselectivity in Asymmetric Transfer Hydrogenation of Ketones. (deposited 02 Aug 2018 06:25)
- N,O- vs N,C-Chelation in Half-Sandwich Iridium Complexes: A Dramatic Effect on Enantioselectivity in Asymmetric Transfer Hydrogenation of Ketones. (deposited 02 Aug 2018 09:56) [Currently Displayed]