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Nitrile ylides also known as nitrilium ylides or nitrilium methylides, are generally reactive intermediates [1] formally consisting of a carbanion of an alkyl or similar group bonded to the nitrogen atom of a cyanide unit. With a few exceptions, they cannot be isolated.
A phosphonium ylide can be prepared rather straightforwardly. Typically, triphenylphosphine is allowed to react with an alkyl halide in a mechanism analogous to that of an S N 2 reaction. This quaternization forms an alkyltriphenylphosphonium salt, which can be isolated or treated in situ with a strong base (in this case, butyllithium) to form ...
Unfortunately, these two forces often cancel each other, causing poor diastereoselection in 1,3-dipolar cycloaddition. Examples of substrate-controlled diastereoselective 1,3-dipolar cycloadditions are shown below. First is the reaction between benzonitrile N-benzylide and methyl acrylate.
The Stetter reaction is a reaction used in organic chemistry to form carbon-carbon bonds through a 1,4-addition reaction utilizing a nucleophilic catalyst. [1] While the related 1,2-addition reaction, the benzoin condensation , was known since the 1830s, the Stetter reaction was not reported until 1973 by Dr. Hermann Stetter. [ 2 ]
The nucleophilic phosphine attacks the azide at the electrophilic terminal nitrogen. Through a four-membered transition state, N 2 is lost to form an aza-ylide. The unstable ylide is hydrolyzed to form phosphine oxide and a primary amine. However, this reaction is not immediately bioorthogonal because hydrolysis breaks the covalent bond in the ...
In organic chemistry, a 1,3-dipolar compound or 1,3-dipole is a dipolar compound with delocalized electrons and a separation of charge over three atoms.They are reactants in 1,3-dipolar cycloadditions.
The structure of a nitrile: the functional group is highlighted blue. In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group.The name of the compound is composed of a base, which includes the carbon of the −C≡N, suffixed with "nitrile", so for example CH 3 CH 2 C≡N is called "propionitrile" (or propanenitrile). [1]
The Ritter reaction proceeds by the electrophilic addition of either a carbenium ion or covalent species [5] [6] to the nitrile. The resulting nitrilium ion is hydrolyzed to the desired amide. Primary, [ 7 ] secondary, [ 4 ] tertiary, [ 8 ] and benzylic [ 9 ] alcohols , [ 1 ] as well as tert -butyl acetate, [ 10 ] also successfully react with ...