2114-90-1

Upstream product

• 81750-86-9 19,20-didehydroyohimban-17-one 
• 81750-84-7 16,17,19,20-tetrahydro-17-methoxy-yohimban-21-one 
• 81750-85-8 16,17,19,20-tetrahydro-17-methoxy-yohimban 
• 81768-64-1 (20α)-18,19-didehydroyohimban-17-one 
• 88966-92-1 dimethyl (20α)-17-oxoyohimban-1,16-dicarboxylate 
• 64999-56-0 methyl (20α)-18,19-didehydro-17-oxoyohimban-16-carboxylate 
• 79-22-1 methyl chloroformate 
• 36069-26-8 methyl (20α)-15,16-didehydro-17-oxoyohimban-16-carboxylate 
• 1218-41-3 1-<2-(1H-indol-3-yl)ethyl>-4-piperidinone 
• 132672-75-4 methyl 1,2,6,7,8,8a-hexahydro-2-<2-(1H-indol-3-yl)ethyl>-6-oxo-5-isoquinolinecarboxylate 
• 37734-07-9 methyl endo/exo-3-(bicyclo<2,2,1>hept-5-en-2-yl)-3-oxopropanoate 
• 92579-46-9 2,3-dihydro-1-<2-(1H-indol-3-yl)ethyl>-4(1H)-pyridinone 
• 26822-37-7 N,N-dimethyl-4-oxopiperidinium iodide 
• 37734-05-7 Methyl 3-oxo-4-pentenoate 

Downstream Products

• 84-37-7 (+/-)-β-yohimbine 
• 84-37-7 3α-15α-20β-17α-hydroxylyohimbine-16α-carboxylic acid methyl ester 

Relevant academic research and scientific papers

A Concise, Enantioselective Approach for the Synthesis of Yohimbine Alkaloids

We report a concise, enantioselective synthesis of the yohimbine alkaloids (-)-rauwolscine and (-)-alloyohimbane. The key transformation involves a highly enantio- and diastereoselective NHC-catalyzed dimerization and an amidation/N-acyliminium ion cyclization sequence to furnish four of the five requisite rings and three of the five stereocenters in two operations. This route also provides efficient access to all four diastereomeric arrangements of the core stereotriad of the yohimbine alkaloids from a common intermediate. This platform approach in combination with the ability to access both enantiomers from the carbene-catalyzed reaction is a powerful strategy that can produce a wide range of complex alkaloids and related structures for future biomedical investigations.

Total Syntheses of Yohimbe Alkaloids, with Stereoselection for the Normal, Allo, and 3-Epiallo Series, Based on Annelations of 4-Methoxy-1,2-dihydropyridones

N--2,3-dihydro-4-pyridone (31) was generated in two steps (77percent yield) from tryptamine and N-methyl-4-piperidone methiodide.Its cyclization (90percent yield) and oxidation (91percent yield) provided the tetracyclic analogue 32.O-Methylation and Robinson-type annelation of these vinylogous lactams (the latter in form of its Na-carbamate) furnished the dienones 38 (64percent) and 43 (90percent).Further elaboration by cyclization and/or reduction reactions selectively provided the 15,16-didehydroyohimbinones 7 and 44.Their reductions then led to yohimbinone (52, 20percent overall yield from tryptamine), alloyohimbinone (11, 19percent overall yield), and 3-epi-alloyohimbinone (10, 23percent overall yield), which led to yohimbine (3), β-yohimbine (9), 3-epi-alloyohimbine (53), and 3-epi-17-epi-alloyohimbine (54).

Photocyclisation of Enamides. Part 27. Total Syntheses of(+/-)-Yohimbine, (+/-)-Alloyohimbine, and (+/-)-19,20-Didehydroyohimbines

Total syntheses of five indole alkaloids, (+/-)-yohimbine (10), (+/-)-alloyohimbine (11), and three (+/-)-19,20-didehydroyohimbines (15a, b, and c) (for the first time) were completed from a single common key intermediate (4) via a route involving the ste

INDOLE ALKALOID SYNTHESIS

The lecture describes the total synthesis of pseudoyohimbine and an approach to the deserpidine group of indole alkaloids by way of the route of nucleophilic addition to a pyridinium salt followed by acid-induced ring closure.