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

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.

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5339-5350 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Subba Cheekatla ◽  
Darshan Mhatre

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.


2015 ◽  
Vol 11 ◽  
pp. 1514-1519 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Ajay Kumar Chinnam ◽  
Mukesh Eknathrao Shirbhate

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.


2018 ◽  
Vol 14 ◽  
pp. 2537-2544 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Saidulu Todeti ◽  
Vikas R Aswar

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.


2015 ◽  
Vol 11 ◽  
pp. 1259-1264 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Ongolu Ravikumar

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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