Hydrogen bonding in organic synthesis V: potassium fluoride in carboxylic acids as an alternative to crown ether with acid salts in the preparation of phenacyl esters

1977 ◽  
Vol 18 (7) ◽  
pp. 599-602 ◽  
Author(s):  
James H. Clark ◽  
Jack M. Miller
2014 ◽  
Vol 70 (a1) ◽  
pp. C987-C987
Author(s):  
Andreas Lemmerer ◽  
Lee Madeley ◽  
Mark Smith

The similarity of crystal engineering to organic synthesis has been noted by Desiraju and many concepts and strategies have been successfully transferred. We aim to combine the two fields of research into one new concept called "Covalent Assistance to Supramolecular Synthesis". The supramolecular reagent isonicotinic acid hydrazide (isoniazid) is a promising molecule in the supramolecular synthesis of multi-component molecular complexes (Lemmerer at al., 2010). Due to the covalent reaction of the carbohydrazide functional group with simple ketones and aldehydes, the hydrogen bonding functionality of isoniazid can be modified, where two of the hydrogen bond donors are replaced with hydrogen bonding "inert" hydrocarbons (Lemmerer et al., 2011). The "modifiers" bonded to the isoniazid then give a measure of control of the outcome of the supramolecular synthesis with various carboxylic acids depending on the identity and steric size of the modifier used. The steric size itself can be used to shield or to "mask" the remaining hydrogen bonding functionality of isoniazid such that common homomeric and heteromeric interactions are prevented from taking place.


Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>


2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>


Author(s):  
Zhaona Liu ◽  
Huacheng Zhang ◽  
Jie Han

Combination of Nobel macrocycle—crown ether and star macrocycle—pillararenes together in organic synthesis and material science is significant to grant thus obtained hybrid systems, rigid/flexible structural architecture, induced planar chirality, negative...


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