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Synthesis and Characterization of Bimetallic Nanoclusters Stabilized by Chiral and Achiral Polyvinylpyrrolidinones. Catalytic C(sp3)–H Oxidation
Fan, Huafang Tong, Zongbo Ren, Zhaoyang Mishra, Kanchan Morita, Shunya Edouarzin, Edruce Gorla, Lingaraju Averkiev, Boris Day, Victor W. Hua, Duy H.
Fan, Huafang
Tong, Zongbo
Ren, Zhaoyang
Mishra, Kanchan
Morita, Shunya
Edouarzin, Edruce
Gorla, Lingaraju
Averkiev, Boris
Day, Victor W.
Hua, Duy H.
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Abstract
Second-generation chiral-substituted poly-N-vinylpyrrolidinones (CSPVPs) (−)-1R and (+)-1S were synthesized by free-radical polymerization of (3aR,6aR)- and (3aS,6aS)-5-ethenyl-tetrahydro-2,2-dimethyl-4H-1,3-dioxolo[4,5-c]pyrrol-4-one, respectively, using thermal and photochemical reactions. They were produced from respective d-isoascorbic acid and d-ribose. In addition, chiral polymer (−)-2 was also synthesized from the polymerization of (S)-3-(methoxymethoxy)-1-vinylpyrrolidin-2-one. Molecular weights of these chiral polymers were measured using HRMS, and the polymer chain tacticity was studied using 13C NMR spectroscopy. Chiral polymers (−)-1R, (+)-1S, and (−)-2 along with poly-N-vinylpyrrolidinone (PVP, MW 40K) were separately used in the stabilization of Cu/Au or Pd/Au nanoclusters. CD spectra of the bimetallic nanoclusters stabilized by (−)-1R and (+)-1S showed close to mirror-imaged CD absorption bands at wavelengths 200–300 nm, revealing that bimetallic nanoclusters’ chiroptical responses are derived from chiral polymer-encapsulated nanomaterials. Chemo-, regio-, and stereo-selectivity was found in the catalytic C–H group oxidation reactions of complex bioactive natural products, such as ambroxide, menthofuran, boldine, estrone, dehydroabietylamine, 9-allogibberic acid, and sclareolide, and substituted adamantane molecules, when catalyst Cu/Au (3:1) or Pd/Au (3:1) stabilized by CSPVPs or PVP and oxidant H2O2 or t-BuOOH were applied. Oxidation of (+)-boldine N-oxide 23 using NMO as an oxidant yielded 4,5-dehydroboldine 27, and oxidation of (−)-9-allogibberic acid yielded C6,15 lactone 47 and C6-ketone 48.
Description
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Organic Chemistry, copyright © 2022 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.joc.2c00449.
Date
2022-05-05
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American Chemical Society
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Keywords
Bimetals, Molecules, Nanoclusters, Oxidation, Polymers
Citation
Fan, H., Tong, Z., Ren, Z., Mishra, K., Morita, S., Edouarzin, E., Gorla, L., Averkiev, B., Day, V. W., & Hua, D. H. (2022). Synthesis and Characterization of Bimetallic Nanoclusters Stabilized by Chiral and Achiral Polyvinylpyrrolidinones. Catalytic C(sp3)-H Oxidation. The Journal of organic chemistry, 87(10), 6742–6759. https://doi.org/10.1021/acs.joc.2c00449