SYNTHESIS OF MORPHINE FRAGMENTS SPIRO[BENZOFURAN-3(2H),4'-PIPERIDINE]AND OCTAHYDRO-1H-BENZOFURO[3,2-E]ISOQUINOLINE BY INTRAMOLECULAR HECK REACTION

As a better alternative to radical cyclization, 2-bromo-6-methoxypheno xy)2-methyl-1,2,3,4,5,6,7,8- octahydroisoquinoline (2) and its 1-oxo a nalog 3 underwent Pd-catalyzed intramolecular cyclization to give the tetracyclic (ACNO) morphine fragments 5 and 6 respectively. -methoxyph enoxy)methyl]-1-ethoxycarbonyl-1,2,5,6,- tetrahydropyridine (11) react ed similarly to provide the tricyclic ANO fragment 12 in 70% yield and 45% e.e. when a Pd-(S)-BINAP complex was used as the catalyst. (C) 19 97 Elsevier Science Ltd.