Synthesis and Characterization of Bimetallic Nanoclusters Stabilized by Chiral and Achiral Polyvinylpyrrolidinones. Catalytic C(sp3)–H Oxidation

• DOI: 10.1021/acs.joc.2c00449
• Publication Date: 2022-05-05T16:24:34Z
• Authors: Huafang Fan; Zongbo Tong; Zhaoyang Ren; Kanchan Mishra; Shunya Morita; Edruce Edouarzin; Lingaraju Gorla; Boris Averkiev; Victor W. Day; Duy H. Hua
• Keywords: Bimetallic strip; Nanoclusters

Second-generation chiral-substituted poly-N-vinylpyrrolidinones (CSPVPs) (-)-1R and (+)-1S were synthesized by free-radical polymerization of (3aR,6aR)- (3aS,6aS)-5-ethenyl-tetrahydro-2,2-dimethyl-4H-1,3-dioxolo[4,5-c]pyrrol-4-one, respectively, using thermal photochemical reactions. They produced from respective d-isoascorbic acid d-ribose. In addition, chiral polymer (-)-2 was also the (S)-3-(methoxymethoxy)-1-vinylpyrrolidin-2-one. Molecular weights these polymers measured HRMS, chain tacticity studied 13C NMR spectroscopy. Chiral (-)-1R, (+)-1S, along with poly-N-vinylpyrrolidinone (PVP, MW 40K) separately used in stabilization Cu/Au or Pd/Au nanoclusters. CD spectra bimetallic nanoclusters stabilized showed close to mirror-imaged absorption bands at wavelengths 200-300 nm, revealing that nanoclusters' chiroptical responses are derived polymer-encapsulated nanomaterials. Chemo-, regio-, stereo-selectivity found catalytic C-H group oxidation reactions complex bioactive natural products, such as ambroxide, menthofuran, boldine, estrone, dehydroabietylamine, 9-allogibberic acid, sclareolide, substituted adamantane molecules, when catalyst (3:1) CSPVPs PVP oxidant H2O2 t-BuOOH applied. Oxidation (+)-boldine N-oxide 23 NMO an yielded 4,5-dehydroboldine 27, (-)-9-allogibberic C6,15 lactone 47 C6-ketone 48.