Indication of Pd–C or Cu–C Intermediates in Bimetallic Nanoclusters During Pd/Au-PVP- or Cu/Au-PVP-Catalyzed Oxidations of endo-4-Oxatricyclo[5.2.1.02,6]-8-decene and Tetrahydro-γ-carbolines

• DOI: 10.1055/a-2001-6888
• Publication Date: 2022-12-21T00:27:40Z
• Authors: Duy H. Hua; Shunya Morita; Zhaoyang Ren; Lingaraju Gorla; Zongbo Tong; Edruce Edouarzin; Boris Averkiev; Victor W. Day
• Keywords: Bimetallic strip; Norbornene; Tetrahydrofuran

Abstract Catalytic oxidation of tricyclic endo-norbornene-fused tetrahydrofuran with the bimetallic nanocluster Cu/Au-PVP in presence H2O2 or t-BuOOH as oxidant leads to C–H bond adjacent ether function give 4-oxa-tricyclo[5.2.1.0]-8,9-exo-epoxydecane, however, Pd/Au-PVP takes place at C=C double same epoxide and oxidative three-bond forming dimeric product, dodecahydro-1,4:6,9-dimethanodibenzofurano[2,3-b:7,8-b′]bisoxolane. Formation latter product suggests involvement a reactive Pd–C intermediate. Similarly, C–C bond-forming reactions are observed cycloaddition N2-Boc-1,2,3,4-tetrahydro-γ-carbolines 2,3-dihydroxybenzoic acid (2–5 mol%) 25 °C, providing two-bond-forming [4+2] cycloadducts. Under similar reaction conditions, did not produce corresponding cycloadduct, indicating need for complexation between Cu carboxylic group allylic amine γ-carbolines during cyclization reaction. The reported intermolecular coupling using catalysts under conditions °C unprecedented.