scholarly journals Enhanced clickability of doubly sterically-hindered aryl azides

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Suguru Yoshida ◽  
Akira Shiraishi ◽  
Kimiyuki Kanno ◽  
Takeshi Matsushita ◽  
Kohei Johmoto ◽  
...  
Keyword(s):  
Aryl Azides ◽  
Sterically Hindered

scholarly journals Further enhancement of the clickability of doubly sterically-hindered aryl azides by para-amino substitution

2018 ◽  
Vol 54 (96) ◽  
pp. 13499-13502 ◽  
Author(s):  
Suguru Yoshida ◽  
Junko Tanaka ◽  
Yoshitake Nishiyama ◽  
Yuki Hazama ◽  
Takeshi Matsushita ◽  
...  
Keyword(s):  
Amino Group ◽  
Aryl Azides ◽  
Sterically Hindered

Introduction of an amino group at the para position of doubly sterically-hindered aryl azides significantly enhances their clickability with cyclooctynes.

Pyrolysis of aryl azides. IV. Neighbouring group effects by ortho carbonyl groups

1977 ◽  
Vol 30 (12) ◽  
pp. 2669 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Carbonyl Groups ◽  
Aryl Azides ◽  
Phenyl Azide ◽  
Sterically Hindered ◽  
Group Effects

The question of the mechanism by which ortho carbonyl groups enhance the rate of pyrolysis of aryl azides is examined. Rate measurements on sterically hindered 1-(2-azidophenyl)ethan-1-ones are consistent with the pericyclic mechanism proposed by Dyall and Kemp1 but not with the intramolecular 1,3-dipolar addition route put forward by Hall, Behr and Reed.2 A definitive test of mechanism is also provided by 1- azidoanthraquinone and 1-(2-azidophenyl)-2,2-dimethylpropan-1-for both of which the formation of a 1,3-dipolar adduct is precluded on steric grounds but the pericyclic process is not. At 393.2 K, these two azides pyrolyse 7385 and 61.7 times faster than phenyl azide, respectively.

Nickel-Catalyzed Regioselective Hydroalkylation of 1,3-Dienes with Hydrazones

2019 ◽  
Author(s):  
Leiyang Lv ◽  
Dianhu Zhu ◽  
Zihang Qiu ◽  
Jianbin Li ◽  
Chao-Jun Li
Keyword(s):  
Catalytic Method ◽  
Unsaturated Hydrocarbons ◽  
Carbon Nucleophiles ◽  
Aryl Aldehydes ◽  
Aldehydes And Ketones ◽  
Sterically Hindered

Hydroalkylation of unsaturated hydrocarbons with unstablized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydroalkylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acted as both the sources of unstabilized carbanions and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a novel and reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.

Synthesis of Conjugated Triynes via Alkyne Metathesis

2019 ◽  
Author(s):  
Idriss Curbet ◽  
Sophie Colombel-Rouen ◽  
Romane Manguin ◽  
Anthony Clermont ◽  
Alexandre Quelhas ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
High Selectivity ◽  
Alkyne Metathesis ◽  
Cross Metathesis ◽  
Synthetic Strategy ◽  
Sterically Hindered ◽  
Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

Utilizing o-quinone methide chemistry: synthesis of sterically hindered acridin-4-ols

2021 ◽  
Vol 31 (2) ◽  
pp. 262-264
Author(s):  
Svetlana K. Polyakova ◽  
Tatyana V. Balashova ◽  
Roman V. Rumyantcev ◽  
Maxim V. Arsenyev ◽  
Georgy K. Fukin ◽  
...  
Keyword(s):  
Quinone Methide ◽  
Sterically Hindered
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