Rhodium(III)-Catalyzed Diastereoselective Ring-Opening of 7‑Azabenzonorbornadienes with Aromatic Ketoximes: Synthesis of Benzophenanthridine Derivatives
journal contributionposted on 25.11.2019, 16:33 by Varathan Vinayagam, Arumugam Mariappan, Mrinmoy Jana, Masilamani Jeganmohan
A rhodium(III)-catalyzed redox-neutral ring-opening of 7-azabenzonorbornadienes with aromatic ketoximes giving 2-arylated hydronaphthylamines in a highly diastereoselective manner is described. Later, the 2-arylated hydronaphthylamines were converted into highly sensitive 13,14-dehydro benzophenanthridine derivatives by HCl hydrolysis. Further, 13,14-dehydro benzophenanthridines were aromatized into biologically important benzophenanthridine derivatives in the presence of DDQ. A possible reaction mechanism was proposed and supported by deuterium labeling studies and isolation of a rhodacycle intermediate.