Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

Abstract

SummaryThe synthesis of 2-tetralones through the cyclization of δ-aryl-β-dicarbonyl substrates by using CAN is described. Appropriately functionalized aromatic substrates undergo intramolecular cyclizations generating 2-tetralone derivatives in moderate to good yields. DFT computational studies indicate that successful formation of 2-tetralones from δ-aryl-β-dicarbonyl radicals is dependent on the stability of the subsequent cyclohexadienyl radical intermediates. Furthermore, DFT computational studies were used to rationalize the observed site selectivity in the 2-tetralone products.

A Domino Dearomative ipso-Annulation/Desymmetrization Approach: Stereoselective Access to Tricyclic Alkaloid Skeletons

“…Based on the results observed and previous reports, ,, we propose a plausible mechanism as shown in Scheme b. First, from 2a , the oxidant (CAN) produces the radical A , which upon regioselective addition to the alkene of 1a generates the radical B .…”

Ce-catalyzed regioselective synthesis of pyrazoles from 1,2-diols via tandem oxidation and C–C/C–N bond formation

“…CAN which acts both as an oxidant and a Lewis acid has been utilized as a catalyst for alcohol oxidation and N-heterocycle synthesis. 15 So, we envisaged the regioselective synthesis of pyrazoles by tandem oxidation/ring cyclization of 1,2-diols with hydrazones employing CAN as a redox-active metal catalyst under an oxygen atmosphere.…”

Total Synthesis of (±)-Spiroaxillarone A

“…As shown in Table , the initial attempts using tetrahydrocurcumin ( 7a ) as the substrate and CAN or Mn­(OAc) 3 as the single-electron oxidant led to no reaction in low temperature and decomposition in higher temperature (entries 1–2). The free phenol hydroxy would be responsible for decomposition in this relatively mild condition; therefore, the phenol hydroxy should be protected.…”