TOTAL SYNTHESIS OF THE SPERMIDINE ALKALOID (-(9S,13S)-ISOCYCLOCELABENZINE())

An asymmetric synthesis of the spermidine alkaloid (+)-isocyclocelaben zine (1a) is reported using (3S)-3-amino-3-phenylpropanoic acid as the chiral building block. The 1,2,3,4-tetrahydroisoquinolin-1-one fragme nt 9 was synthesized by a modified Bischler-Napieralski reaction. The resulting C(13)-epimers were separated by semi-preparative HPLC. The r elative configuration of the naturally occurring alkaloid was determin ed by an X-ray crystal structure analysis, which enabled us to determi ne the absolute configuration of natural (+)-1a at both chiral centers to be (9S) and (13S). Copyright (C) 1996 Elsevier Science Ltd