Total Synthesis of Pyrrolidine and Piperidine Natural Products via TMSOTf-Mediated "5/6- endo-dig " Reductive Hydroamination of Enynyl Amines.

Stereoselective syntheses of pyrrolidines and piperidines bearing hydrophobic chains have been achieved through a metal free, Lewis acid-mediated 5/6- endo-dig reductive hydroamination cascade of enynyl amines. The brevity of the developed strategy allowed for the collective stereoselective total synthesis of various alkaloids, including (±)-pyrrolidine cis -225H, (±)- epi -197B, (±)- epi -225C, the family of (+)-solenopsins and (+)-isosolenopsins, and the formal synthesis of (±)-bgugaine and (+)-azimic acid.