131-03-3Relevant articles and documents
Bicyclic Guanidine Catalyzed Asymmetric Tandem Isomerization Intramolecular-Diels-Alder Reaction: The First Catalytic Enantioselective Total Synthesis of (+)-alpha-Yohimbine
Feng, Wei,Jiang, Danfeng,Kee, Choon-Wee,Liu, Hongjun,Tan, Choon-Hong
, p. 390 - 394 (2016)
Hydroisoquinoline derivatives were prepared in moderate to good enantioselectivities via a bicyclic guanidine-catalyzed tandem isomerization intramolecular-Diels-Alder (IMDA) reaction of alkynes. With this synthetic method, the first enantioselective synthesis of (+)-alpha-yohimbine was completed in 9 steps from the IMDA products.
A Concise, Enantioselective Approach for the Synthesis of Yohimbine Alkaloids
Miller, Eric R.,Hovey, M. Todd,Scheidt, Karl A.
, p. 2187 - 2192 (2020/02/04)
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
Kuehne, Martin E.,Muth, Randy S.
, p. 2701 - 2712 (2007/10/02)
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).
