Construction of Tricyclic Nitrogen Heterocycles by Gold(I)‐Catalyzed Cascade Cyclization of Allenynes and Its Application to Polycyclic π‐Electron Systems

2021 ◽  
Author(s):  
Hiroki Komatsu ◽  
Takaya Ikeuchi ◽  
Hitomi Tsuno ◽  
Norihito Arichi ◽  
Kosuke Yasui ◽  
...  
2020 ◽  
Vol 18 (36) ◽  
pp. 7086-7089
Author(s):  
Shanshan Qiao ◽  
Peng-Cheng Qian ◽  
Fan Chen ◽  
Jiang Cheng

An iron-catalyzed radical cascade cyclization of dienes initiated by an alkoxycarbonyl radical has been developed in the presence of (NH4)2S2O8, leading to a series of fused nitrogen heterocyclic compounds under relatively mild reaction conditions.


1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.


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