The total synthesis of (±)-4-demethoxy-10-nordaunomycinone

1987 ◽  
Vol 65 (6) ◽  
pp. 1375-1379 ◽  
Author(s):  
C. M. Wong ◽  
P. M. Gordon ◽  
A. G. Chen ◽  
H. Y. P. Lam
Keyword(s):  
Total Synthesis ◽  
Phthalic Anhydride ◽  
Aluminum Chloride ◽  
Trifluoroacetic Acid ◽  
Nucleophilic Addition ◽  
Mercuric Acetate ◽  
Iron Pentacarbonyl ◽  
Magnesium Bromide ◽  
Acetate Oxidation ◽  
Hydride Reduction

4-Demethoxy-10-nordaunomycinone (4) is synthesized starting with 4,7-dimethoxy-1-indanone (8). Nucleophilic addition of ethynyl magnesium bromide to 8 followed by mercuric acetate oxidation and iron pentacarbonyl – tri-n-butyltin hydride reduction gave 4,7-dimethoxy-1-acetylindane (16). Condensation of 16 with phthalic anhydride followed by methylation with dimethylsulfate and oxidation gave 22, which was epimerized to 24 by 2,2-dimethoxypropane and trifluoroacetic acid. Demethylation of 24 with aluminum chloride gave the 4-demethoxy-10-nordaunomycinone (4).

The Keck Synthesis of Epothilone B

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Total Synthesis ◽  
Secondary Alcohol ◽  
Allylic Alcohol ◽  
Ring Closing Metathesis ◽  
Relative Configuration ◽  
University Of Utah ◽  
Epothilone B ◽  
Hydride Reduction ◽  
Epothilone A ◽  
The University

The total synthesis of Epothilone B 4, the first natural product (with Epothilone A) to show the same microtubule-stabilizing activity as paclitaxel (Taxol®), has attracted a great deal of attention since that activity was first reported in 1995. The total synthesis of 4 devised (J. Org. Chem. 2008, 73, 9675) by Gary E. Keck of the University of Utah was based in large part on the stereoselective allyl stannane additions (e.g. 1 + 2 → 3 ) that his group originated. The allyl stannane 2 was prepared from the acid chloride 5. Exposure of 5 to Et3N generated the ketene, that was homologated with the phosphorane 6 to give the allene ester 7. Cu-mediated conjugate addition of the stannylmethyl anion 8 then delivered 2. The silyloxy aldehyde 1 was prepared from the ester 9 by reduction with Dibal. Felkincontrolled 1,2-addition of the allyl stannane 2 established the relative configuration of the secondary alcohol of 3, that was then used to control the relative configuration of the new alcohol in 10. Addition of the crotyl borane 12 to the derived aldehyde 11 also proceeded with high diastereocontrol. The other component of 4 was prepared from the aldehyde 14. Enantioselective allylation, by the method the authors developed, delivered the alcohol 16. The Z trisubstituted alkene was then assembled by condensing the aldehyde 17 with the phosphorane 18. Dibal reduction of the product lactone 19 gave a diol, the allylic alcohol of which was selectively converted to the chloride with the Corey-Kim reagent. Hydride reduction then delivered the desired homoallylic alcohol, that was converted to the phosphonium salt 21. Condensation of 21 with 13 gave the diene, that was carried on to Epothilone B 4. The synthesis of Epothilone B 4 as originally conceived by the authors depended on ring-closing metathesis of the triene 22. They prepared 22, but on exposure to the second-generation Grubbs catalyst it was converted only to 23. The authors concluded that the trans acetonide kept 22 in a conformation that did not allow the desired macrocyclization.

Total Synthesis of (–)-Alstofolinine A: Selected Furan Oxidation/ Cyclization Cascade

Synlett ◽  
2019 ◽  
Vol 31 (01) ◽  
pp. 7-12 ◽  
Author(s):  
Ye Zhang ◽  
Lei Zhang ◽  
Xiangbing Qi
Keyword(s):  
Total Synthesis ◽  
Common Core ◽  
Nucleophilic Addition ◽  
Addition Reaction ◽  
Indole Alkaloids ◽  
Indole Alkaloid ◽  
Asymmetric Total Synthesis ◽  
Ring Systems ◽  
Synthetic Strategy ◽  
Nucleophilic Addition Reaction

Indole-fused tetracyclic ring systems containing nitrogen atoms are common core skeletons of many indole alkaloids such as sarpagine, macroline, and ajmaline. Efficient and stereoselective construction of these ring systems can promote the development of the corresponding alkaloid syntheses. In this article, we briefly summarize our current progress toward the application of the aza-Achmatowicz reaction and indole nucleophilic addition reaction cascade for the first asymmetric total synthesis of the macroline-type indole alkaloid (–)-Alstofolinine A. Our synthetic strategy is based on furan oxidation/rearrangement and proceeds from easily accessible materials such as indole and furan derivatives.

THE PREPARATION OF ERYTHRO-3-PENTULOSE

1961 ◽  
Vol 39 (12) ◽  
pp. 2593-2601 ◽  
Author(s):  
R. J. Stoodley
Keyword(s):  
Mercuric Acetate ◽  
Acetate Oxidation

The mercuric acetate oxidation of ribitol yielded a mixture of erythro-3-pentulose and DL-erythro-2-pentulose.

CATALYSTS IN THE PREPARATION OF O-BENZOYLBENZOIC ACID AND ETHYLBENZENES BY THE FRIEDEL AND CRAFTS REACTION

1930 ◽  
Vol 2 (1) ◽  
pp. 31-34 ◽  
Author(s):  
W. Gallay ◽  
G. S. Whitby
Keyword(s):  
Ferric Chloride ◽  
Phthalic Anhydride ◽  
Aluminum Chloride

In the preparation of o-benzoylbenzoic acid from benzene and phthalic anhydride, ferric chloride is a much poorer catalyst than aluminum chloride, but an equimolecular mixture of ferric and aluminum chlorides, although less active than aluminum chloride itself, possesses an activity greater than the sum of the activities of its components separately. Ferric chloride is not a catalyst for the combination of benzene and ethylene. Amalgamated aluminum is a better catalyst than aluminum chloride for both of the reactions mentioned.

CALYCANTHINE: III. SOME DEGRADATION EXPERIMENTS

1938 ◽  
Vol 16b (12) ◽  
pp. 432-437 ◽  
Author(s):  
Léo Marion ◽  
Richard H. F. Manske
Keyword(s):  
Phthalic Anhydride ◽  
Mercuric Acetate ◽  
Degradation Products ◽  
Hydriodic Acid ◽  
Red Phosphorus ◽  
Hydrogen Atoms ◽  
Oxygenated Products

The identification of 4-carboline amongst the degradation products obtained by the action of selenium on calycanthine makes it possible to account for 12 of the 22 carbon atoms of calycanthine. The fusion of calycanthine with phthalic anhydride yielded 12: 13-benzcanthin-11-one, which was also obtained from tryptamine and phthalic anhydride. On the basis of these observations a partial formula for calycanthine is suggested. The oxidation of calycanthine with mercuric acetate eliminated two hydrogen atoms, giving rise to a base which can be reduced again to calycanthine. Reduction of calycanthine with hydriodic acid and red phosphorus yielded quinoline, and methylation in the presence of air gave rise to oxygenated products containing three nitrogen atoms, and to methylamine. The phenylcarbamyl derivative of calycanthine has the same ultimate composition as, but differs from, that of N-methyltryptamine.

scholarly journals Studies on 1-Azabicyclo Compounds. XXIII. Mercuric Acetate Oxidation of Deoxynupharidine

1975 ◽  
Vol 95 (4) ◽  
pp. 439-444
Author(s):  
YOSHIO ARATA ◽  
SHINGO YASUDA ◽  
RUMIKO FUJITA
Keyword(s):  
Mercuric Acetate ◽  
Acetate Oxidation
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