Studies in biomimetic alkaloid syntheses. 14. Controlled, selective syntheses of catharanthine and tabersonine, and related desethyl compounds, through generation of 15-oxosecodine intermediates
118. The constitution of yohimbine and related alkaloids. Part VI. The synthesis of 1 : 2 : 3 : 4 : 6 : 7 : 12 : 12b-octahydro-2-ketoindolo-(2 : 3-a)pyridocoline and 1 : 2 : 3 : 4-tetrahydroindolo(2 : 3-a)pyridocoline