The Hayashi rearrangement is the chemical reaction of ortho-benzoylbenzoic acids catalyzed by sulfuric acid or phosphorus pentoxide. [1] [2]
This reaction proceeds through electrophilic acylium ion attack with a spiro intermediate. [3] [4]
The Hayashi rearrangement is the chemical reaction of ortho-benzoylbenzoic acids catalyzed by sulfuric acid or phosphorus pentoxide. [1] [2]
This reaction proceeds through electrophilic acylium ion attack with a spiro intermediate. [3] [4]
In organic chemistry, allenes are organic compounds in which one carbon atom has double bonds with each of its two adjacent carbon centres. Allenes are classified as cumulated dienes. The parent compound of this class is propadiene, which is itself also called allene. Compounds with an allene-type structure but with more than three carbon atoms are members of a larger class of compounds called cumulenes with X=C=Y bonding.
Cubane is a synthetic hydrocarbon compound that consists of eight carbon atoms arranged at the corners of a cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane is one of the Platonic hydrocarbons and a member of the prismanes. It was first synthesized in 1964 by Philip Eaton and Thomas Cole. Before this work, Eaton believed that cubane would be impossible to synthesize due to the "required 90 degree bond angles". The cubic shape requires the carbon atoms to adopt an unusually sharp 90° bonding angle, which would be highly strained as compared to the 109.45° angle of a tetrahedral carbon. Once formed, cubane is quite kinetically stable, due to a lack of readily available decomposition paths. It is the simplest hydrocarbon with octahedral symmetry.
In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.
Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula C
14H
8O
2. Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone wherein the keto groups are located on the central ring. It is a building block of many dyes and is used in bleaching pulp for papermaking. It is a yellow, highly crystalline solid, poorly soluble in water but soluble in hot organic solvents. It is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol. It is found in nature as the rare mineral hoelite.
Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the "parent" of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.
Walden inversion is the inversion of a stereogenic center in a chiral molecule in a chemical reaction. Since a molecule can form two enantiomers around a stereogenic center, the Walden inversion converts the configuration of the molecule from one enantiomeric form to the other. For example, in an SN2 reaction, Walden inversion occurs at a tetrahedral carbon atom. It can be visualized by imagining an umbrella turned inside-out in a gale. In the Walden inversion, the backside attack by the nucleophile in an SN2 reaction gives rise to a product whose configuration is opposite to the reactant. Therefore, during SN2 reaction, 100% inversion of product takes place. This is known as Walden inversion.
The Ferrier rearrangement is an organic reaction that involves a nucleophilic substitution reaction combined with an allylic shift in a glycal. It was discovered by the carbohydrate chemist Robert J. Ferrier.
The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation.
Iodine pentafluoride is an interhalogen compound with chemical formula IF5. It is one of the fluorides of iodine. It is a colorless liquid, although impure samples appear yellow. It is used as a fluorination reagent and even a solvent in specialized syntheses.
1,3,5,7-Cyclooctatetraene (COT) is an unsaturated derivative of cyclooctane, with the formula C8H8. It is also known as [8]annulene. This polyunsaturated hydrocarbon is a colorless to light yellow flammable liquid at room temperature. Because of its stoichiometric relationship to benzene, COT has been the subject of much research and some controversy.
Prismane or 'Ladenburg benzene' is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973.
The Carroll rearrangement is a rearrangement reaction in organic chemistry and involves the transformation of a β-keto allyl ester into a α-allyl-β-ketocarboxylic acid. This organic reaction is accompanied by decarboxylation and the final product is a γ,δ-allylketone. The Carroll rearrangement is an adaptation of the Claisen rearrangement and effectively a decarboxylative allylation.
The Bamberger rearrangement is the chemical reaction of phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols. It is named for the German chemist Eugen Bamberger (1857–1932).
The Ramberg–Bäcklund reaction is an organic reaction converting an α-halo sulfone into an alkene in presence of a base with extrusion of sulfur dioxide. The reaction is named after the two Swedish chemists Ludwig Ramberg and Birger Bäcklund. The carbanion formed by deprotonation gives an unstable episulfone that decomposes with elimination of sulfur dioxide. This elimination step is considered to be a concerted cycloelimination.
The Boyland–Sims oxidation is the chemical reaction of anilines with alkaline potassium persulfate, which after hydrolysis forms ortho-hydroxyl anilines. The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents.
The Smiles rearrangement is an organic reaction and a rearrangement reaction named after British chemist Samuel Smiles. It is an intramolecular nucleophilic aromatic substitution of the type:
The Stieglitz rearrangement is a rearrangement reaction in organic chemistry which is named after the American chemist Julius Stieglitz (1867–1937) and was first investigated by him and Paul Nicholas Leech in 1913. It describes the 1,2-rearrangement of trityl amine derivatives to triaryl imines. It is comparable to a Beckmann rearrangement which also involves a substitution at a nitrogen atom through a carbon to nitrogen shift. As an example, triaryl hydroxylamines can undergo a Stieglitz rearrangement by dehydration and the shift of a phenyl group after activation with phosphorus pentachloride to yield the respective triaryl imine, a Schiff base.
Melengestrol is a steroidal progestin of the 17α-hydroxyprogesterone group and an antineoplastic drug which was never marketed. An acylated derivative, melengestrol acetate, is used as a growth promoter in animals.
1,2-Dimethyldiborane is an organoboron compound with the formula [(CH3)BH2]2. Structurally, it is related to diborane, but with methyl groups replacing terminal hydrides on each boron. It is the dimer of methylborane, CH3BH2, the simplest alkylborane. 1,2-Dimethyldiborane can exist in a cis- and a trans arrangement. 1,2-Dimethyldiborane is an easily condensed, colorless gas that ignites spontaneously in air.