scholarly journals Total Synthesis of Mycalisine B

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 226 ◽  
Author(s):  
Haixin Ding ◽  
Zhizhong Ruan ◽  
Peihao Kou ◽  
Xiangyou Dong ◽  
Jiang Bai ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Large Scale ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Key Steps

The first total synthesis of the marine nucleoside Mycalisine B—a naturally occurring and structurally distinct 4,5-unsaturated 7-deazapurine nucleoside—has been accomplished in 10 linear steps with 27.5% overall yield from commercially available 1,2,3,5-tetra-O-acetyl-ribose and tetracyanoethylene. Key steps of the approach include: (1) I2 catalyzed acetonide formation from 1,2,3,5-tetra-O-acetylribose and acetone at large scale; (2) Vorbrüggen glycosylation using N4-benzoyl-5-cyano-6-bromo-7H-pyrrolo[2,3–d]pyrimidine as a nucleobase to avoid formation of N-3 isomer; (3) mild and scalable reaction conditions.

Total synthesis of zincophorin

2005 ◽  
Vol 77 (7) ◽  
pp. 1131-1137 ◽  
Author(s):  
Janine Cossy ◽  
Christophe Meyer ◽  
Magali Defosseux ◽  
Nicolas Blanchard
Keyword(s):  
Double Bond ◽  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Naturally Occurring ◽  
Key Steps ◽  
Stereogenic Center

A total synthesis of the naturally occurring ionophore zincophorin has been realized. The key steps are an intramolecular oxymercuration of a cyclopropanemethanol for the elaboration of the tetrahydropyran ring and a Carroll–Claisen rearrangement to control the configuration of the double bond at C20–C21 as well as the stereogenic center at C21.

scholarly journals Total Synthesis of Surinamensinols A and B

SynOpen ◽  
2020 ◽  
Vol 04 (04) ◽  
pp. 84-88
Author(s):  
Ahmed Al-Harrasi ◽  
Satya Kumar Avula ◽  
Biswanath Das ◽  
Rene Csuk ◽  
Ahmed Al-Rawahi
Keyword(s):  
Total Synthesis ◽  
Allyl Alcohol ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Ethyl Lactate ◽  
Naturally Occurring ◽  
Cross Coupling Reaction ◽  
Synthetic Sequence ◽  
Key Steps ◽  
Single Approach

AbstractAn efficient total synthesis of the naturally occurring anti-inflammatory and antitumour 8-O-4′-neolignans, surinamensinols A and B, has been accomplished from commercially available allyl alcohol and (S)-ethyl lactate. The synthetic sequence involves a palladium-catalysed Suzuki–Miyaura cross-coupling reaction followed by a chiral Mitsunobu­ reaction as the key steps. This is the first report of the simultaneous stereoselective total synthesis of surinamensinols A and B through a single approach involving only six steps.

scholarly journals Ring Expansions of Cyclopropanated Carbohydrates

2021 ◽  
Author(s):  
◽  
Rhys Antony Batchelor
Keyword(s):  
Total Synthesis ◽  
Single Molecule ◽  
Ring Expansion ◽  
Reaction Conditions ◽  
Ring Expansions ◽  
Naturally Occurring ◽  
Synthetic Chemist ◽  
High Yields ◽  
A Minor

<p>The combination of cyclopropanes and carbohydrates functionality within a single molecule gives the synthetic chemist an interesting combination of reactivity and chirality to expand further upon. However, until recently relatively little work has been done in this field. Following the report of methodology to convert cyclopropanated carbohydrates into oxepines in high yields, this investigation set out to improve the selectivity of the rearrangement and also investigate the further utility of the subsequent products. Focused investigation of the starting substrates and reaction conditions led to a minor adaptation of the previously successful methodology for the ring expansion of cyclopropanated glycals. This resulted in a substantial increase in the selectivity of the reaction to generate oxepine rings in good to excellent yields with a range of nucleophiles. One of the oxepines was subsequently chosen for elaboration into a range of synthons for further investigations. These yielded a variety of oxepanes in good yields with well defined stereo- and regioselective outcomes. In the course of these reactions several unexpected products were isolated. These were further investigated with labelling experiments and a mechanism for their formation was proposed. Finally the methodology was applied to the total synthesis of a naturally occurring oxepine containing compound. Despite the apparent simplicity of the target, the effort was ultimately unsuccessful.</p>

scholarly journals Ring Expansions of Cyclopropanated Carbohydrates

2021 ◽  
Author(s):  
◽  
Rhys Antony Batchelor
Keyword(s):  
Total Synthesis ◽  
Single Molecule ◽  
Ring Expansion ◽  
Reaction Conditions ◽  
Ring Expansions ◽  
Naturally Occurring ◽  
Synthetic Chemist ◽  
High Yields ◽  
A Minor

<p>The combination of cyclopropanes and carbohydrates functionality within a single molecule gives the synthetic chemist an interesting combination of reactivity and chirality to expand further upon. However, until recently relatively little work has been done in this field. Following the report of methodology to convert cyclopropanated carbohydrates into oxepines in high yields, this investigation set out to improve the selectivity of the rearrangement and also investigate the further utility of the subsequent products. Focused investigation of the starting substrates and reaction conditions led to a minor adaptation of the previously successful methodology for the ring expansion of cyclopropanated glycals. This resulted in a substantial increase in the selectivity of the reaction to generate oxepine rings in good to excellent yields with a range of nucleophiles. One of the oxepines was subsequently chosen for elaboration into a range of synthons for further investigations. These yielded a variety of oxepanes in good yields with well defined stereo- and regioselective outcomes. In the course of these reactions several unexpected products were isolated. These were further investigated with labelling experiments and a mechanism for their formation was proposed. Finally the methodology was applied to the total synthesis of a naturally occurring oxepine containing compound. Despite the apparent simplicity of the target, the effort was ultimately unsuccessful.</p>

Total Synthesis of Macaranin B

2021 ◽  
Author(s):  
Shintaro Matsumoto ◽  
Akio Aoyama ◽  
Shinnosuke Wakamori ◽  
Hidetoshi Yamada
Keyword(s):  
Total Synthesis ◽  
Michael Addition ◽  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Oxidative Coupling Reaction ◽  
Naturally Occurring ◽  
Key Steps

Abstract This study describes the total synthesis of macaranin B, a naturally occurring ellagitannin containing 1-O-galloyl and 3,6-O-macaranoyl groups in an axial-rich D-glucose. The Key steps of the synthesis include an oxidative coupling reaction of galloyl groups with 1,2,4-orthoacetylglucose moiety and oxa-Michael addition/elimination using an orthoquinone monoketal. This facilitates the construction of the macaranoyl group and the first total synthesis of macaranin B.

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

scholarly journals Applications of the Horner-Wadsworth-Emmons olefination in modern natural product synthesis

Synthesis ◽  
2021 ◽  
Author(s):  
Dávid Roman ◽  
Maria Sauer ◽  
Christine Beemelmanns
Keyword(s):  
Natural Products ◽  
Natural Product ◽  
Natural Product Synthesis ◽  
Reaction Conditions ◽  
Comprehensive Review ◽  
Modern Natural ◽  
Key Steps ◽  
Synthetic Approaches

Here, we have summarized more than 30 representative natural product syntheses published in 2015 to 2020 that employ one or more Horner-Wadsworth-Emmons (HWE) reactions. We comprehensively describe the applied phosphonate reagents, HWE reaction conditions and key steps of the total synthetic approaches. Our comprehensive review will support future synthetic approaches and serve as guideline to find the best HWE conditions for the most complicated natural products known

scholarly journals Discovery of naturally occurring inhibitors against SARS-CoV-2 3CLpro from Ginkgo biloba leaves via large-scale screening

Fitoterapia ◽  
2021 ◽  
pp. 104909
Author(s):  
Yuan Xiong ◽  
Guang-Hao Zhu ◽  
Hao-Nan Wang ◽  
Qing Hu ◽  
Li-Li Chen ◽  
...  
Keyword(s):  
Ginkgo Biloba ◽  
Large Scale ◽  
Naturally Occurring ◽  
Large Scale Screening
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