scholarly journals Amethyrin-type expanded porphyrins that display anti-aromatic character upon protonation

2020 ◽  
Vol 56 (69) ◽  
pp. 9994-9997 ◽  
Author(s):  
Harrison D. Root ◽  
Daniel N. Mangel ◽  
James T. Brewster ◽  
Hadiqa Zafar ◽  
Adam Samia ◽  
...  

The use of protonation to switch nonaromatic expanded porphyrins to their corresponding anti-aromatic forms is shown.

2019 ◽  
Author(s):  
Clare Bakewell ◽  
Martí Garçon ◽  
Richard Y Kong ◽  
Louisa O'Hare ◽  
Andrew J. P. White ◽  
...  

The reactions of an aluminium(I) reagent with a series of 1,2-, 1,3- and 1,5-dienes are reported. In the case of 1,3-dienes the reaction occurs by a pericyclic reaction mechanism, specifically a cheletropic cycloaddition, to form aluminocyclopentene containing products. This mechanism has been interrogated by stereochemical experiments and DFT calculations. The stereochemical experiments show that the (4+1) cycloaddition follows a suprafacial topology, while calculations support a concerted albeit asynchronous pathway in which the transition state demonstrates aromatic character. Remarkably, the substrate scope of the (4+1) cycloaddition includes dienes that are either in part, or entirely, contained within aromatic rings. In these cases, reactions occur with dearomatisation of the substrate and can be reversible. In the case of 1,2- or 1,5-dienes complementary reactivity is observed; the orthogonal nature of the C=C π-bonds (1,2-diene) and the homoconjugated system (1,5-diene) both disfavour a (4+1) cycloaddition. Rather, reaction pathways are determined by an initial (2+1) cycloaddition to form an aluminocyclopropane intermediate which can in turn undergo insertion of a further C=C π-bond leading to complex organometallic products that incorporate fused hydrocarbon rings.


Author(s):  
Hao Wang ◽  
Junhua Chen ◽  
Chunguo Duan ◽  
Xuefang Xu ◽  
Yang Zheng ◽  
...  

2013 ◽  
Vol 17 (01n02) ◽  
pp. 27-35 ◽  
Author(s):  
Thanh-Tuan Bui ◽  
Aude Escande ◽  
Christian Philouze ◽  
Gianluca Cioci ◽  
Sudip Ghosh ◽  
...  

A new member of the cyclo[n]pyrrole class of expanded porphyrins was prepared from the corresponding thiophene-containing terpyrrole precursor through use of a mild electrochemical oxidative procedure. The isolated macrocycle, featuring nine heterocyclic subunits directly connected through their α,α′-positions, is the largest cyclo[n]pyrrole derivative reported to date. The structure obtained via synchrotron radiation-based studies revealed a dimeric arrangement involving individual macrocyclic subunits.


1999 ◽  
Vol 103 (33) ◽  
pp. 6669-6672 ◽  
Author(s):  
Jerome M. Schulman ◽  
Raymond L. Disch
Keyword(s):  

2021 ◽  
Vol MA2021-01 (16) ◽  
pp. 761-761
Author(s):  
Gloria Cardenas-Jiron ◽  
Merlys Borges-Martinez ◽  
Nicolas Montenegro-Pohlhammer ◽  
Yoh Yamamoto ◽  
Tunna Baruah ◽  
...  

2018 ◽  
Vol 9 (38) ◽  
pp. 7528-7539 ◽  
Author(s):  
Tomohiro Higashino ◽  
Atsushi Kumagai ◽  
Shigeyoshi Sakaki ◽  
Hiroshi Imahori

The dithieno[3,4-b:3′,4′-d]thiophene unit is a new effective motif to realize the π-system switching of expanded porphyrins.


2004 ◽  
Vol 17 (5) ◽  
pp. 393-398 ◽  
Author(s):  
Jun-ichi Aihara ◽  
Toshimasa Ishida
Keyword(s):  

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