Structural and mechanistic studies of the copper(II)-assisted ortho-hydroxylation of benzoates by trimethylamine N-oxide
N-benzoyl-2-methylalanine (H2L1) is ortho-hydroxylated stereoselectively by trimethylamine N-oxide (TMAO) in the presence of copper(II). The experimental structure of [Cu(L1)(TMAO)2] suggests that the oxygen transfer agent TMAO transfers the oxygen atom to copper(II), and (L1)2−, coordinated to copp...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2002
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| In: |
Journal of organometallic chemistry
Year: 2002, Volume: 641, Issue: 1/2, Pages: 71-80 |
| ISSN: | 1872-8561 |
| DOI: | 10.1016/S0022-328X(01)01291-8 |
| Online Access: | Verlag, Pay-per-use, Volltext: http://dx.doi.org/10.1016/S0022-328X(01)01291-8 Verlag, Pay-per-use, Volltext: http://www.sciencedirect.com/science/article/pii/S0022328X01012918 
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| Author Notes: | Wim Buijs, Peter Comba, Danny Corneli, Hans Pritzkow |
| Summary: | N-benzoyl-2-methylalanine (H2L1) is ortho-hydroxylated stereoselectively by trimethylamine N-oxide (TMAO) in the presence of copper(II). The experimental structure of [Cu(L1)(TMAO)2] suggests that the oxygen transfer agent TMAO transfers the oxygen atom to copper(II), and (L1)2−, coordinated to copper(II) by a carboxylate oxygen and the amide nitrogen donor, is well pre-organized for an oxygen transfer from copper to the ortho carbon atom of the benzene ring. Product analyses as a function of reaction time of the copper(II)-mediated ortho-hydroxylation reaction with H2L1 and various derivatives support the suggestion of a reactive copper-oxo or copper-hydroxo intermediate, stabilized by a five-membered chelate with hard carboxylate and N-amide donors. The analysis also suggests that there is a pre-equilibrium with a Cu:L=1:1 ratio, and this might involve Cu/L2−/TMAO or dicopper complexes. Depending on the ligand H2L, complexation with the salicylate product may inhibit the ortho-hydroxylation reaction. |
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| Item Description: | Gesehen am 06.03.2018 Article was first available online on 14 December 2001 |
| Physical Description: | Online Resource |
| ISSN: | 1872-8561 |
| DOI: | 10.1016/S0022-328X(01)01291-8 |