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Synthesis, characterization, and structures of oxovanadium(V) complexes of Schiff bases of beta-amino alcohols as tunable catalysts for the asymmetric oxidation of organic sulfides and asymmetric alkynylation of aldehydes.
Dalton Trans. 2007 Jan 07DT

Abstract

Oxovanadium(V) complexes and with general formula VO(L3*)(OR5) were prepared in quantitative yields in alcohol (R5OH) from reactions of VO(O-i-Pr)3 and tridentate Schiff bases of beta-amino alcohols having one or two stereogenic centers, (HO)C*(R1)(R2)C*H(R3)N[double bond, length as m-dash]CH(2-OH-3,5-R4(2)-C6H2) (H2L3*). The alkoxy OR5 ligand exchanges readily with the alcoholic molecule in the solvent. Crystal structures of and were determined to be five-coordinate square pyramidal monomers. However, 1H NMR spectra of the complexes reveal two sets of signals, indicating the presence of two isomers in solution. The two isomers are suggested to be the endo/exo pair or the monomer/dimer pair. Asymmetric oxidations of methyl phenyl sulfide catalyzed by catalyst precursors were demonstrated to afford the chiral sulfoxide in yields and ee values similar to those obtained from the in situ-formed catalytic systems of VO(acac)2 and corresponding Schiff base ligands. Complexes and are also good catalysts for asymmetric alkynyl additions to aldehydes. Structural differences between the oxovanadium complexes, for inducing high stereoselectivities in the asymmetric oxidation of organic sulfides and the asymmetric alkynyl addition to aldehydes, are rationalized.

Authors+Show Affiliations

Department of Chemistry, National Chung-Hsing University, Taichung, 402, Taiwan.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17160179

Citation

Hsieh, Sheng-Hsiung, et al. "Synthesis, Characterization, and Structures of oxovanadium(V) Complexes of Schiff Bases of Beta-amino Alcohols as Tunable Catalysts for the Asymmetric Oxidation of Organic Sulfides and Asymmetric Alkynylation of Aldehydes." Dalton Transactions (Cambridge, England : 2003), 2007, pp. 97-106.
Hsieh SH, Kuo YP, Gau HM. Synthesis, characterization, and structures of oxovanadium(V) complexes of Schiff bases of beta-amino alcohols as tunable catalysts for the asymmetric oxidation of organic sulfides and asymmetric alkynylation of aldehydes. Dalton Trans. 2007.
Hsieh, S. H., Kuo, Y. P., & Gau, H. M. (2007). Synthesis, characterization, and structures of oxovanadium(V) complexes of Schiff bases of beta-amino alcohols as tunable catalysts for the asymmetric oxidation of organic sulfides and asymmetric alkynylation of aldehydes. Dalton Transactions (Cambridge, England : 2003), (1), 97-106.
Hsieh SH, Kuo YP, Gau HM. Synthesis, Characterization, and Structures of oxovanadium(V) Complexes of Schiff Bases of Beta-amino Alcohols as Tunable Catalysts for the Asymmetric Oxidation of Organic Sulfides and Asymmetric Alkynylation of Aldehydes. Dalton Trans. 2007 Jan 7;(1)97-106. PubMed PMID: 17160179.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Synthesis, characterization, and structures of oxovanadium(V) complexes of Schiff bases of beta-amino alcohols as tunable catalysts for the asymmetric oxidation of organic sulfides and asymmetric alkynylation of aldehydes. AU - Hsieh,Sheng-Hsiung, AU - Kuo,Ya-Pei, AU - Gau,Han-Mou, Y1 - 2006/11/03/ PY - 2006/12/13/pubmed PY - 2007/4/4/medline PY - 2006/12/13/entrez SP - 97 EP - 106 JF - Dalton transactions (Cambridge, England : 2003) JO - Dalton Trans IS - 1 N2 - Oxovanadium(V) complexes and with general formula VO(L3*)(OR5) were prepared in quantitative yields in alcohol (R5OH) from reactions of VO(O-i-Pr)3 and tridentate Schiff bases of beta-amino alcohols having one or two stereogenic centers, (HO)C*(R1)(R2)C*H(R3)N[double bond, length as m-dash]CH(2-OH-3,5-R4(2)-C6H2) (H2L3*). The alkoxy OR5 ligand exchanges readily with the alcoholic molecule in the solvent. Crystal structures of and were determined to be five-coordinate square pyramidal monomers. However, 1H NMR spectra of the complexes reveal two sets of signals, indicating the presence of two isomers in solution. The two isomers are suggested to be the endo/exo pair or the monomer/dimer pair. Asymmetric oxidations of methyl phenyl sulfide catalyzed by catalyst precursors were demonstrated to afford the chiral sulfoxide in yields and ee values similar to those obtained from the in situ-formed catalytic systems of VO(acac)2 and corresponding Schiff base ligands. Complexes and are also good catalysts for asymmetric alkynyl additions to aldehydes. Structural differences between the oxovanadium complexes, for inducing high stereoselectivities in the asymmetric oxidation of organic sulfides and the asymmetric alkynyl addition to aldehydes, are rationalized. SN - 1477-9226 UR - https://www.unboundmedicine.com/medline/citation/17160179/Synthesis_characterization_and_structures_of_oxovanadium_V__complexes_of_Schiff_bases_of_beta_amino_alcohols_as_tunable_catalysts_for_the_asymmetric_oxidation_of_organic_sulfides_and_asymmetric_alkynylation_of_aldehydes_ L2 - https://doi.org/10.1039/b613212j DB - PRIME DP - Unbound Medicine ER -