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A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations.
J Am Chem Soc. 2014 Aug 13; 136(32):11362-81.JA

Abstract

A Cu(I) catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI═NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C═C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products.

Authors+Show Affiliations

Department of Chemistry, Missouri University of Science and Technology , Rolla, Missouri 65409, United States.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

25025754

Citation

Bagchi, Vivek, et al. "A Versatile Tripodal Cu(I) Reagent for C-N Bond Construction Via Nitrene-transfer Chemistry: Catalytic Perspectives and Mechanistic Insights On C-H Aminations/amidinations and Olefin Aziridinations." Journal of the American Chemical Society, vol. 136, no. 32, 2014, pp. 11362-81.
Bagchi V, Paraskevopoulou P, Das P, et al. A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations. J Am Chem Soc. 2014;136(32):11362-81.
Bagchi, V., Paraskevopoulou, P., Das, P., Chi, L., Wang, Q., Choudhury, A., Mathieson, J. S., Cronin, L., Pardue, D. B., Cundari, T. R., Mitrikas, G., Sanakis, Y., & Stavropoulos, P. (2014). A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations. Journal of the American Chemical Society, 136(32), 11362-81. https://doi.org/10.1021/ja503869j
Bagchi V, et al. A Versatile Tripodal Cu(I) Reagent for C-N Bond Construction Via Nitrene-transfer Chemistry: Catalytic Perspectives and Mechanistic Insights On C-H Aminations/amidinations and Olefin Aziridinations. J Am Chem Soc. 2014 Aug 13;136(32):11362-81. PubMed PMID: 25025754.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations. AU - Bagchi,Vivek, AU - Paraskevopoulou,Patrina, AU - Das,Purak, AU - Chi,Lingyu, AU - Wang,Qiuwen, AU - Choudhury,Amitava, AU - Mathieson,Jennifer S, AU - Cronin,Leroy, AU - Pardue,Daniel B, AU - Cundari,Thomas R, AU - Mitrikas,George, AU - Sanakis,Yiannis, AU - Stavropoulos,Pericles, Y1 - 2014/08/05/ PY - 2014/7/16/entrez PY - 2014/7/16/pubmed PY - 2014/7/16/medline SP - 11362 EP - 81 JF - Journal of the American Chemical Society JO - J Am Chem Soc VL - 136 IS - 32 N2 - A Cu(I) catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI═NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C═C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products. SN - 1520-5126 UR - https://www.unboundmedicine.com/medline/citation/25025754/A_versatile_tripodal_Cu_I__reagent_for_C_N_bond_construction_via_nitrene_transfer_chemistry:_catalytic_perspectives_and_mechanistic_insights_on_C_H_aminations/amidinations_and_olefin_aziridinations_ L2 - https://doi.org/10.1021/ja503869j DB - PRIME DP - Unbound Medicine ER -
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