Physical Sciences and Mathematics Commons^™

Shorter And Improved Access To The Key Tetracyclic Core Of Sarpagine-Macroline-Ajmaline Indole Alkaloids: The Total Synthesis Of Alkaloids Macrocarpines A-G, Talcarpine, N(4)-Methyl-N(4),21-Secotalpinine, Deoxyperaksine, Dihydroperaksine, Talpinine, O-Acetyltalpinine, And N(4)-Methyltalpinine, Md Toufiqur Rahman

Theses and Dissertations

Extension of the asymmetric Pictet-Spengler (P-S) reaction to bulkier Nb-alkylated tryptophan derivatives resulted in a shorter and improved stereospecific access to the key bicyclo[3.3.1]nonane framework of bioactive C-19 methyl substituted sarpagine/macro-line/ajmaline indole alkaloids with excellent diastereoselectivity via internal asymmetric induction. The asymmetric Pictet-Spengler/Dieckmann protocol with bulky Nb-alkyl substituted systems enabled a more direct and two-step shorter route to this key architecture. Complete stereocontrol of the C-19 methyl function in either the α- or β-configuration was achieved which would enable one to gain rapid access to the crucial intermediates for the total synthesis of any member of this group of seventy …