New protocols for the assembly of the tetracyclic framework associated with the aromatic erythrina alkaloids.
[reaction: see text] Treatment of the anion derived from the ring-fused gem-dichlorocyclopropane 4c with silver tetrafluoroborate afforded the spirocyclic compound 17 in 74% yield. Product 17 was readily converted, over three steps, into the beta-iodoethyl derivative 20 and treatment of this latter compound with n-Bu(3)SnH then afforded, in 93% yield and via a radical addition/elimination sequence, compound 2 incorporating the ABCD framework of the aromatic erythrina alkaloids.
Stanislawski
Pauline C
PC
Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra.
Willis
Anthony C
AC
Banwell
Martin G
MG