scholarly journals Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

2015 ◽  
Vol 11 ◽  
pp. 1514-1519 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Ajay Kumar Chinnam ◽  
Mukesh Eknathrao Shirbhate
Keyword(s):  
Grignard Reaction ◽  
Ring Closing Metathesis ◽  
Design And Synthesis ◽  
Synthetic Strategy ◽  
Fischer Indolization ◽  
Grignard Addition ◽  
Key Steps

We demonstrate a new synthetic strategy to cyclophanes containing thiophene and indole moieties via Grignard addition, Fischer indolization and ring-closing metathesis as key steps.

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.

Design and synthesis of polycyclic bisindoles via Fischer indolization and ring-closing metathesis as key steps

2016 ◽  
Vol 57 (50) ◽  
pp. 5605-5607 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Subba Rao Cheekatla ◽  
Ajay Kumar Chinnam ◽  
Tanu Jain
Keyword(s):  
Ring Closing Metathesis ◽  
Design And Synthesis ◽  
Fischer Indolization ◽  
Key Steps

scholarly journals Spiro annulation of cage polycycles via Grignard reaction and ring-closing metathesis as key steps

2015 ◽  
Vol 11 ◽  
pp. 1367-1372 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Mohammad Saifuddin ◽  
Rashid Ali ◽  
Gaddamedi Sreevani
Keyword(s):  
Single Crystal ◽  
Diels Alder ◽  
Grignard Reaction ◽  
X Ray Diffraction ◽  
Ring Closing Metathesis ◽  
Cage Compounds ◽  
X Ray ◽  
Synthetic Strategy ◽  
Cage Compound ◽  
Key Steps

A simple synthetic strategy to C 2-symmetric bis-spiro-pyrano cage compound 7 involving ring-closing metathesis is reported. The hexacyclic dione 10 was prepared from simple and readily available starting materials such as 1,4-naphthoquinone and cyclopentadiene. The synthesis of an unprecedented octacyclic cage compound through intramolecular Diels–Alder (DA) reaction as a key step is described. The structures of three new cage compounds 7, 12 and 18 were confirmed by single crystal X-ray diffraction studies.

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.

Synthesis of Aza-polyquinanes via Fischer Indolization and Ring-Rearrangement Metathesis as Key Steps

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 3989-3997 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Ramakrishna Reddy Keesari ◽  
Saima Ansari
Keyword(s):  
Synthetic Strategy ◽  
Fischer Indolization ◽  
Key Steps ◽  
Medium Rings

Herein, we describe a simple synthetic strategy to assemble aza-polyquinane systems containing an indole motif by employing the Fischer indolization and ring-rearrangement metathesis as key steps. The precursor used here is exo-dicyclopentadienone, which is derived from less explored exo-dicyclopentadiene. By using this approach, several aza-polyquinanes that contain indole units and fused medium rings (eight- and nine-membered rings) were synthesized in good yields.

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

2015 ◽  
Vol 11 ◽  
pp. 1373-1378 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Rama Gunta
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Ring Systems ◽  
Design And Synthesis ◽  
Synthetic Strategy ◽  
Diels Alder Reaction ◽  
Fused Ring ◽  
Materials Used ◽  
Key Steps

Here, we describe a new and simple synthetic strategy to various polycyclic sulfones via Diels–Alder reaction and ring-rearrangement metathesis (RRM) as the key steps. This approach delivers tri- and tetracyclic sulfones with six (n = 1), seven (n = 2) or eight-membered (n = 3) fused-ring systems containing trans-ring junctions unlike the conventional all cis-ring junctions generally obtained during the RRM sequence. Interestingly the starting materials used are simple and commercially available.

scholarly journals Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

2014 ◽  
Vol 10 ◽  
pp. 2664-2670 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Mirtunjay Kumar Dipak
Keyword(s):  
Claisen Rearrangement ◽  
Diels Alder ◽  
Ring Closing Metathesis ◽  
Design And Synthesis ◽  
Grignard Addition ◽  
Economical Process

Intricate caged molecular frameworks are assembled by an atom economical process via a Diels–Alder (DA) reaction, a Claisen rearrangement, a ring-closing metathesis (RCM) and an alkenyl Grignard addition. The introduction of olefinic moieties in the pentacycloundecane (PCUD) framework at appropriate positions followed by RCM led to the formation of novel heptacyclic cage systems.

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.

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