Ketene cycloadditions are the reactions of the pi system of ketenes with unsaturated compounds to provide four-membered or larger rings. [2+2], [3+2]...

[2+2] cycloaddition. The example shows the synthesis of a β-lactam by the reaction of a ketene with an imine (see Staudinger synthesis): Ketenes are generally...

suprafacial-antarafacial sense (syn/anti stereochemistry), such as the cycloaddition reactions of ketene and allene derivatives, in which the orthogonal set of p orbitals...

enol ethers of esters (−OR) or carboxylic acids (−COOH) are called silyl ketene acetals and have the general structure R3Si−O−C(OR)=CR2. These compounds...

Hermann Staudinger's work with ketenes published in 1912 covered both [2+2] cycloadditions, where one molecule of a ketene reacted with an unsaturated compound...

via this mode. Ketenes are a large class of reactants favoring [2 + 2] cycloaddition with olefins. The MO analysis of ketene cycloaddition is rendered complicated...

stable alkylidene ketenes via N2/CO exchange at atmospheric pressure. Alkylidene ketenes can readily dimerize and participate in cycloaddition reactions. Often...

Staudinger ketene-imine cycloaddition, is a chemical synthesis in which an imine 1 reacts with a ketene 2 through a non-photochemical 2+2 cycloaddition to produce...

addition reaction with a range of other chemicals, particularly ketene cycloadditions, or dimerisation to diketene. With this approach it is possible...

compound is converted into a ketene by loss of dinitrogen with accompanying 1,2-rearrangement. The Wolff rearrangement yields a ketene as an intermediate product...

viable. Some classes of pericyclic reactions, such as the [2+2] ketene cycloaddition reactions, can be 'controversial' because their mechanism is sometimes...

unsaturated compounds which undergo [2+2] cycloadditions with the in situ generated ketenes. When ketenes are formed in the presence of alkynes they...

1-ethoxycyclobutene-3-one, which is prepared from the cycloaddition of ethoxyacetylene to ketene. A variety of substituted 1,3-Cyclobutanediones form upon...

connected by a pair of new carbon-carbon bonds, the result of the [4+4] cycloaddition. It reverts to anthracene thermally or with UV irradiation below 300 nm...

the following scheme: The synthesis begins with photochemical [2+2]cycloaddition of ethene on the cyclohexene derivative 1 to produce the bicyclic compound...

ethylene and ketene. The activation energy for this [2+2] cycloelimination is 52 kcal/mol. The reverse reaction, the [2+2] cycloaddition of ketene and ethylene...

in the ketene structure R1R2C=C=O, diphenyl ketene is a heterocumulene. The most important reaction of diphenyl ketene is the [2+2] cycloaddition at C-C...

are generally favored over ketene acetals. The high stereospecificity and stereoselectivity inherent in many TMM cycloaddition reactions is a significant...

Cycloaddition 1,3-Dipolar cycloaddition Azide-alkyne Huisgen cycloaddition Diels–Alder reaction Nitrone-olefin (3+2) cycloaddition Staudinger ketene-imine...

computational studies. The new mechanism involves formation of a vinyl ketene. The Vanderwal group has also reported the synthesis of 4-stannyldienals...

N-sulfinylaniline. Sulfinyl amines are dienophile. They undergo [2+2] cycloaddition to ketenes. According to X-ray crystallography, sulfinylamines have planar...

Tsutomu (2003). "Exclusive Formation of α-Methyleneoxetanes in Ketene−Alkene Cycloadditions. Evidence for Intervention of Both an α-Methyleneoxetane and...

potassium carbonate leads to what may be viewed as 2+3 cycloaddition of the nitrogen analogue of a ketene to form the imidazole ring. "European Public Assessment...

metallacyclopropanone, which is a resonance form of the metallated ketene. With ketene reactivity, the species could be trapped by several nucleophiles...

also undergo cyclization, e.g. azide alkyne Huisgen cycloaddition to give triazoles. Cycloaddition processes involving alkynes are often catalyzed by metals...

(RC(O)CHN2) product undergoes the metal-catalyzed Wolff rearrangement to form a ketene, which hydrates to the acid. The rearrangement leaves untouched the stereochemistry...

the potential of PCO towards cycloadditions. They found that the anion could react in a [2+2] fashion with a diphenyl ketene to produce the first isolatable...

{R-C(O)CN}}}+{\ce {H2O}}} Acetyl cyanide is also prepared by hydrocyanation of ketene: CH 2 = C = O + H CN ⟶ H 3 C − C ( O ) CN {\displaystyle {\ce {CH2=}}{\color...

A. R.; Nguyen, H. D.; Chung, J. Y. L. (1984). "Cationic cyclization of ketene dithioacetals. A general synthesis of pyrrolizidine, indolizidine, and quinolizidine...

possess a rich cycloaddition chemistry, including both [4+2] and [2+2] modes of addition, as well as undergoing formal cycloaddition processes catalyzed...