Collect. Czech. Chem. Commun. 1999, 64, 203-216

Intramolecular N-Acyliminium Ion-Olefin Cyclization in the Synthesis of Optically Pure Isoquinoline Derivatives: Control of Stereochemistry and Application to Synthesis of Morphine Alkaloids

Patricia Bottari, Mary Ann A. Endoma, Tomáš Hudlický*, Ion Ghiviriga and Khalil A. Abboud

Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, U.S.A.


The 3-[2-(cyclohex-1-eneyl)ethyl]-[1,3]oxazoline-2,4-dione derivatives 9, 14 and 16 were subjected to hydride reduction followed by acid-catalyzed olefin-N-acyliminium ion cyclization to afford a series of perhydroisoquinolines 10, 11a, 11b, 19a-19c, 20a, 20b and 21. A mechanism was proposed that accounts for the observed stereoselectivity of the cyclization reactions based on the neighboring group participation by a benzoate group.

Keywords: N-Acyliminium ion; Isoquinolines; Stereochemistry; Morphine; Alkaloids; Biooxidation.