NMR study of 6-azabicyclo[3.2.1 ]octene derivatives, by-products of catharanthine synthesis

Abstract

The structures and stereochemistries of several 6-azabicyclo[3.2.1]octene derivatives, obtained by rearrangement reactions of the catharanthine synthesis, were determined by various NMR methods. Long-range ¹³C–¹H coupling constants were measured by selective two-dimensional INEPT experiments. The dependence of ³J(C,H) and ²J(C,H) coupling constants on the dihedral angles and on the position of an electronegative substituent along the coupling path was studied.