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 ^[1]. This organic reaction is accompanied by decarboxylation and the final product is a γ,δ-allylketone. The Carrol rearrangement is an adaptation of the Claisen rearrangement. A rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. ... Jump to: navigation, search Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds that by definition contain carbon. ... Beta (upper case Î’, lower case β) is the second letter of the Greek alphabet. ... A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ... An allyl group is an alkene hydrocarbon group with the formula H2C=CH-CH2-. It is made up of a vinyl group, CH2=CH-, attached to a methylene -CH2. ... Jump to: navigation, search In organic chemistry and biochemistry, esters are rubbish compounds where an organic group (symbolised by R in this article) replaces a hydrogen atom (or more than one) in an oxygen acid. ... Alpha (uppercase Α, lowercase α) is the first letter of the Greek alphabet. ... An allyl group is an alkene hydrocarbon group with the formula H2C=CH-CH2-. It is made up of a vinyl group, CH2=CH-, attached to a methylene -CH2. ... Beta (upper case Î’, lower case β) is the second letter of the Greek alphabet. ... A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ... Structure of a carboxylic acid Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)-OH, usually written as COOH. The salts and anions of carboxylic acids are called carboxylates generally. ... Organic reactions are chemical reactions between organic compounds. ... A Decarboxylation is any chemical reaction in which a carboxyl group (-COOH) is split off from a compound as carbon dioxide (CO2). ... Gamma (upper case Γ, lower case γ) is the third letter of the Greek alphabet. ... Delta (upper case Δ, lower case δ) is the fourth letter of the Greek alphabet. ... An allyl group is an alkene hydrocarbon group with the formula H2C=CH-CH2-. It is made up of a vinyl group, CH2=CH-, attached to a methylene -CH2. ... A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ... Jump to: navigation, search The Claisen rearrangement is a powerful carbon-carbon bond forming chemical reaction discovered by Rainer Ludwig Claisen. ...

Reaction mechanism

The Carrol rearrangement in the presence of base and with high reaction temperature (path A) takes place through an intermediate enol which then rearranges in an electrocyclic claisen rearrangement. The follow up is a decarboxylation. With palladium(0) as a catalyst, the reaction is much milder (path B) with an intermediate allyl cation / carboxylic acid anion organometallic complex. The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ... Enol (or, more officially, but less commonly: alkenol) is an alkene with hydroxyl group on one of the carbon atoms of the double bond. ... Jump to: navigation, search The Claisen rearrangement is a powerful carbon-carbon bond forming chemical reaction discovered by Rainer Ludwig Claisen. ... General Name, Symbol, Number palladium, Pd, 46 Chemical series transition metals Group, Period, Block 10, 5, d Appearance silvery white metallic Atomic mass 106. ... Jump to: navigation, search A catalyst (Greek: καταλύτης, catalytēs) is a substance that accelerates the rate (speed) of a chemical reaction without itself being transformed or consumed by the reaction (see also catalysis). ... Organometallic have classically been compounds having bonds between one or more metal atoms and one or more carbon atoms of an organyl group. ...

Asymmetric Carrol rearrangement

One asymmetric Carrol rearrangement is reported ^[2] catalyzed by tris(dibenzylideneacetone)dipalladium(0)), the Trost ligand and naphthol. The two optical isomers of bromochlorofluoromethane Chiral synthesis (also called asymmetric synthesis) is organic synthesis which preserves or introduces a desired chirality. ... Naphthol, Hydroxynaphthalene or Naphthalenol is either of two colorless crystaline solids with the formula C10H7OH. They are positional isomers differing by the location of the hydroxyl group on naphthalene. ...

This reaction delivers one enantiomer with 88% ee. It remains to be seen if this reaction will have a wide scope because the acetamido group is a prerequisite. In chemistry two stereoisomers are said to be enantiomers if they are mirror images of each other. ... In chemistry two stereoisomers are said to be enantiomers if one can be superimposed on the mirror image of the other. ...

References

1. ^  M.F. Carrol, Journal Organic Chemistry, 1940 704
2. ^  Asymmetric Carroll rearrangement of allyl -acetamido--ketocarboxylates catalysed by a chiral palladium complex Ryoichi Kuwano, Naoki Ishida and Masahiro Murakami Chemical Communications, 2005, (31), 3951 - 3952 Abstract