Ring-Closing Metathesis Approach to Cage Propellanes Containing Oxepane and Tetrahydrofuran Hybrid System

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5339-5350 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Subba Cheekatla ◽  
Darshan Mhatre
Keyword(s):  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ring Closing Metathesis ◽  
Cage Compounds ◽  
Transannular Cyclization ◽  
Diels Alder Reaction ◽  
Grignard Addition ◽  
Key Steps ◽  
First Time

The preparation of a variety of structurally interesting oxygenated cage compounds involving atom-economic processes such as Claisen rearrangement, Diels–Alder reaction, [2+2] photocycloaddition, and ring-closing metathesis (RCM) as key steps is reported. For the first time, oxepane ring system is introduced in cage framework using olefin metathesis as a key step. These cage systems assembled here are difficult to prepare by traditional methods. The synthetic sequence described here opens up new routes to higher order polycycles containing heteroatoms without the involvement of protecting groups. Transannular cyclization observed during Grignard addition and the RCM protocol used here may be applicable to generate unknown oxygenated cage systems.

Protecting-Group-Free Total Synthesis of Anticancer (±)-Melotenine A

Synthesis ◽  
2021 ◽  
Author(s):  
Adisak Thanetchaiyakup ◽  
Hassayaporn Rattanarat ◽  
Sudaporn Aree ◽  
Tanwawan Duangthongyou ◽  
Tanin Nanok ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Human Cancer ◽  
Alder Reaction ◽  
Diels Alder ◽  
Protecting Groups ◽  
Protecting Group ◽  
Ring Closing Metathesis ◽  
Human Cancer Cell Lines ◽  
Diels Alder Reaction ◽  
Key Steps

Melotenine A, isolated from Melodinus tenuicaudatus, possesses significant anticancer activity against several human cancer cell lines. The synthesis of (±)-melotenine A was achieved without the use of any protecting groups in 11 steps with an overall yield of 7%. The key steps of our strategy were the Diels–Alder reaction to construct the tetracyclic framework and ring-closing metathesis to form the seven-membered ring of (±)-melotenine A.

scholarly journals Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

2018 ◽  
Vol 14 ◽  
pp. 2468-2481 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Milind Meshram ◽  
Chandravathi Chakkapalli
Keyword(s):  
Recent Work ◽  
Claisen Rearrangement ◽  
Cross Coupling ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enyne Metathesis ◽  
Cross Metathesis ◽  
Diels Alder Reaction ◽  
Synergistic Approach ◽  
Key Steps

This account provides an overview of recent work, including our own contribution dealing with Suzuki–Miyaura cross coupling in combination with metathesis (or vice-versa). Several cyclophanes, polycycles, macrocycles, spirocycles, stilbenes, biaryls, and heterocycles have been synthesized by employing a combination of Suzuki cross-coupling and metathesis. Various popular reactions such as Diels–Alder reaction, Claisen rearrangement, cross-metathesis, and cross-enyne metathesis are used. The synergistic combination of these powerful reactions is found to be useful for the construction of complex targets and fulfill synthetic brevity.

scholarly journals Design and synthesis of C 3-symmetric molecules bearing propellane moieties via cyclotrimerization and a ring-closing metathesis sequence

2018 ◽  
Vol 14 ◽  
pp. 2537-2544 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Saidulu Todeti ◽  
Vikas R Aswar
Keyword(s):  
Benzene Ring ◽  
Alder Reaction ◽  
Diels Alder ◽  
Central Core ◽  
Ring Closing Metathesis ◽  
Design And Synthesis ◽  
Synthetic Strategy ◽  
Diels Alder Reaction ◽  
End Groups ◽  
Key Steps

We have developed an efficient synthetic strategy to assemble C 3-symmetric molecules containing propellane moieties as end groups and a benzene ring as a central core. The synthesis of these C 3-symmetric molecules involves simple starting materials. Our approach to C 3-symmetric compounds relies on a Diels–Alder reaction, cyclotrimerization and ring-closing metathesis as key steps.

scholarly journals Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

2015 ◽  
Vol 11 ◽  
pp. 1259-1264 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Ongolu Ravikumar
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Design And Synthesis ◽  
Diels Alder Reaction ◽  
Grignard Addition ◽  
Synthetic Routes ◽  
Key Steps ◽  
Norbornene Derivatives

Atom efficient processes such as the Diels–Alder reaction (DA) and the ring-rearrangement metathesis (RRM) have been used to design new polycycles. In this regard, ruthenium alkylidene catalysts are effective in realizing the RRM of bis-norbornene derivatives prepared by DA reaction and Grignard addition. Here, fused polycycles are assembled which are difficult to produce by conventional synthetic routes.

scholarly journals Synthesis of propellanes containing a bicyclo[2.2.2]octene unitviathe Diels–Alder reaction and ring-closing metathesis as key steps

RSC Advances ◽  
2018 ◽  
Vol 8 (27) ◽  
pp. 14906-14915 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Sunil Pulletikurti
Keyword(s):  
Convenient Method ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ring Closing Metathesis ◽  
Diels Alder Reaction ◽  
Key Steps

A simple and convenient method to synthesize propellane derivatives containing a bicyclo[2.2.2]octene unit which are structurally similar to 11β-HSD1 inhibitors by sequential usage of the Diels–Alder reaction, C-allylation and ring-closing metathesis (RCM) is reported.

scholarly journals Synthesis of the AB ring system of clifednamide utilizing Claisen rearrangement and Diels–Alder reaction as key steps

2016 ◽  
Vol 14 (3) ◽  
pp. 884-894 ◽  
Author(s):  
Inga Loke ◽  
Guillaume Bentzinger ◽  
Julia Holz ◽  
Aruna Raja ◽  
Aman Bhasin ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Tetramic Acid ◽  
Diels Alder Reaction ◽  
Key Steps ◽  
Ab Ring

A synthesis to the functionalized AB ring system of clifednamide, member of macrocyclic tetramic acid lactams, was developed involving an Ireland–Claisen rearrangement and an intramolecular Diels–Alder reaction.

scholarly journals Synthesis of fluorinated δ-lactams via cycloisomerization of gem-difluoropropargyl amides

2010 ◽  
Vol 6 ◽  
Author(s):  
Satoru Arimitsu ◽  
Gerald B Hammond
Keyword(s):  
Building Blocks ◽  
Alder Reaction ◽  
Diels Alder ◽  
Tandem Reaction ◽  
Enyne Metathesis ◽  
Metathesis Reaction ◽  
Ring Closing Metathesis ◽  
Diels Alder Reaction

gem-Difluoro-1,7-enyne amides are suitable building blocks for the synthesis of difluorodihydropyridinones via a ring-closing metathesis reaction, and of 4,4-difluoro-3-oxoisoquinolines through a ring-closing metathesis–enyne metathesis tandem reaction. These products, in turn, undergo a Diels–Alder reaction to yield heterotricyclic systems in moderate to good yields.

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