Total synthesis of ylango sesquiterpenoids: (+)-cis- and (+)-trans-sativenediol, (+)-helminthosporal, (+)-helminthosporol, prehelminthosporal, prehelminthosporal diethyl acetal, (+)-victoxinine, (+)-isosativenediol

1977 ◽  
Vol 55 (6) ◽  
pp. 1039-1044 ◽  
Author(s):  
Edward Piers ◽  
Hans-Peter Isenring
Keyword(s):  
Total Synthesis ◽  
Trifluoroacetic Acid ◽  
Chromium Trioxide ◽  
Major Product ◽  
Hydroxy Ketone ◽  
Diethyl Acetal ◽  
Total Syntheses ◽  
Tricyclic Ketone ◽  
Cis And Trans ◽  
Synthetic Transformations

Oxidation of the previously prepared olefinic alcohol 26 with chromium trioxide – pyridine in dichloromethane containing trifluoroacetic acid gave the tricyclic ketone 29 as the major product. Hydroxylation of the latter, followed by reduction of the resulting α-hydroxy ketone 31, afforded a 1:1 mixture of (+)-cis- (22) and (+)-trans-sativenediol (23). In view of earlier synthetic transformations reported by a number of different researchers, the present work also constitutes formal total syntheses of the enantiomers of the following sesquiterpenoids: (−)-helminthosporal (1), (−)-helminthosporol (2), prehelminthosporal (3), prehelminthosporal diethyl acetal (4), (−)-victoxinine (8), and (−)-isosativenediol (19).

A convenient entry into the rhoeadan skeleton. Total synthesis of (±) cis-alpinigenine

1982 ◽  
Vol 60 (21) ◽  
pp. 2678-2686 ◽  
Author(s):  
Ijaz Ahmad ◽  
Victor Snieckus
Keyword(s):  
Total Synthesis ◽  
Polyphosphoric Acid ◽  
Chromium Trioxide ◽  
Total Syntheses ◽  
Diisobutylaluminum Hydride ◽  
Hydride Reduction ◽  
Villiger Oxidation ◽  
Parallel Series

Condensation of 4-bromoisochroman-3-one (8a) with N-methyl-3,4-dimethoxy-β-phenethylamine (7) provides the aminolactone 9a which by diisobutylaluminum hydride reduction followed by polyphosphoric acid mediated cyclization gives the tetracyclic product 10a, thus constituting a convergent, short entry into the rhoeadan alkaloid skeleton. Chromium trioxide oxidation of 10a affords a low yield of the corresponding lactone 11a. A parallel series of reactions starting from 7,8-dimethoxy-4-bromoisochroman-3-one (8b), prepared either via Baeyer–Villiger oxidation of 4,5-dimethoxy-2-indanone (14) or, more conveniently, via benzeneboronic acid assisted condensation of 3-hydroxy-4-methoxyphenylacetic acid (18) with formaldehyde, yields 7,8,12,13-tetramethoxy-3-methylrhoeadan (10b). Oxidation of compound 10b with chromium trioxide gives the corresponding lactone 11b also in low yield. Since 11b has been previously converted into (±)-cis-alpinigenine (11c) and (±)-cis-alpinine(11d), this work constitutes total syntheses of these alkaloids.

Short Protecting Group-free Syntheses of CDE Synthon of Racemic Camptothecin

2020 ◽  
Vol 17 (7) ◽  
pp. 588-591
Author(s):  
Pingxuan Shao ◽  
Wei Lu ◽  
Lei Wang
Keyword(s):  
Total Synthesis ◽  
Future Development ◽  
Protecting Group ◽  
Short Route ◽  
The Future ◽  
Tricyclic Ketone

A practical and concise total synthesis of tricyclic ketone 7 (CDE ring), a valuable intermediate for the synthesis of racemic camptothecin and analogs, was described (8 chemical steps and 29% overall yield). The synthesis starts with two inexpensive, readily available materials and is operationally simple to perform. It is worth mentioning that the reported protecting group-free synthesis, with advantages of a short route, would be helpful for the future development of industry-scale syntheses of camptothecin-family alkaloids.

scholarly journals Xylochemical Synthesis and Biological Evaluation of Shancigusin C and Bletistrin G

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3224
Author(s):  
Leander Geske ◽  
Ulrich Kauhl ◽  
Mohamed E. M. Saeed ◽  
Anja Schüffler ◽  
Eckhard Thines ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Biological Activities ◽  
Biological Evaluation ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Total Syntheses ◽  
Wittig Olefination ◽  
Starting Point ◽  
Perkin Reaction ◽  
Synthesis And Biological Evaluation

The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regioselective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.

Total syntheses and antiproliferative activities of prenostodione and its analogues

2021 ◽  
Author(s):  
Aldahir Ramos Orea ◽  
María Teresa Ramírez-Apan ◽  
Rosa M. Chávez-Santos ◽  
Rodrigo Aguayo-Ortiz ◽  
Clara I Espitia ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Indole Alkaloid ◽  
Total Syntheses ◽  
Antiproliferative Activities

A high-yielding total synthesis of the indole alkaloid prenostodione was completed in 4 steps and 44% overall yield from 1H-indole-3-carboxylic acid. The expedient syntheses of prenostodiones containing distinct substituents at...

(+)-Occidentalol: Absolute Stereostructure and Total Synthesis

1972 ◽  
Vol 50 (3) ◽  
pp. 340-345 ◽  
Author(s):  
Young Amano ◽  
Clayton H. Heathcock
Keyword(s):  
Total Synthesis ◽  
Hydroxy Ketone ◽  
Stage Conversion ◽  
The Absolute

Hydroxy ketone 7 has been prepared from both (+)-dihydrocarvone (3) and (+)-occidentalol (2), thus establishing the absolute stereostructure of the latter. The three-stage conversion of compound 7 into (+)-occidentalol constitutes a total synthesis of the sesquiterpene.

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

Recent Advances in the Total Synthesis of Clavaminols

Synthesis ◽  
2018 ◽  
Vol 50 (23) ◽  
pp. 4569-4576
Author(s):  
Tian Jin ◽  
Lu Zhao ◽  
Zhe-Bin Zheng ◽  
Xiao Liu ◽  
Liang Sun ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Research Groups ◽  
Total Syntheses ◽  
New Class ◽  
Recent Advances ◽  
Molecular Architectures ◽  
Synthetic Approaches ◽  
Long Chain

Clavaminols are a new class of long-chain 2-amino-3-­alkanols that mostly contain 2R,3S-configurations. Owing to their interesting molecular architectures and promising activities, they have ­become popular targets for synthetic organic chemists. In this review, we highlight 12 total syntheses of clavaminols from different research groups during the period 2009 to 2018.1 Introduction2 Synthetic Approaches toward Clavaminols2.1 Total Synthesis by Chemla and Colleagues (2009)2.2 Total Synthesis by Greck and Colleagues (2010)2.3 Total Synthesis by Sutherland and Zaed (2011)2.4 Total Synthesis by Huang and Colleagues (2011)2.5 Total Synthesis by Kotora and Colleagues (2012)2.6 Total Synthesis by Kumar and Colleagues (2013)2.7 Total Synthesis by Prabhavathi Devi and Colleagues (2013 and 2016)2.8 Total Synthesis by Sarabia and Colleagues (2014)2.9 Total Synthesis by Mohapatra and Colleagues (2016)2.10 Total Synthesis by Lu and Colleagues (2016)2.11 Total Synthesis by Jin and Colleagues (2017)2.12 Total Synthesis by Kumar Pandey and Colleagues (2018)3 Conclusion

scholarly journals Total syntheses of all tri-oxygenated 16-phytoprostane classes via a common precursor constructed by oxidative cyclization and alkyl–alkyl coupling reactions as the key steps

2017 ◽  
Vol 15 (44) ◽  
pp. 9408-9414 ◽  
Author(s):  
Jakub Smrček ◽  
Radek Pohl ◽  
Ullrich Jahn
Keyword(s):  
Total Synthesis ◽  
Oxidative Cyclization ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Common Precursor ◽  
Key Steps

A parallel total synthesis of 16-F1t-, 16-E1-phytoprostanes and a first synthesis of 16-D1t-phytoprostanes based on a common precursor are described.

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