Rhodium-Catalyzed Hydrocarbonylation of a Homoallylamine via N–H Activation and Application for Synthesis of Yohimbane Alkaloids

We
describe syntheses of n-yohimbane and alloyohimbane
using Rh-catalyzed hydrocarbonylation, which provides a practical
methodology to synthesize a δ-lactam from a secondary homoallyl
amine. We have also observed an unexpected transformation where the
amine proton served as a hydride to participate in hydrocarbonylation.
The D-labeled experimental results and preliminary DFT-calculations
suggest that the transformation can be rationalized by oxidative cleavage
of the homoallyl amines to a metal hydride complex.