AuBr3-catalyzed thiooxime-to-carbonyl conversion: from chiral aliphatic nitro compounds to ketones without
Jordi Burés1, Carles Isart, Jaume Vilarrasa
1Departament de Química Orgànica, Facultat de Química, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia, Spain.
Abstract:
A new variant of the NO(2)-to-CO transformation (the Nef reaction) that occurs at room temperature under neutral conditions is uncovered. After the conversion of secondary nitroalkanes to phenylsulfenylketimines, these thiooximes are hydrolyzed quantitatively in situ, in THF-H(2)O at pH 7, by addition of AuBr(3) (but not with other MX(n)!). Adducts arising from asymmetric nitro-Michael and nitro-aldol reactions afford 1,4-diketones and alpha-alkoxy ketones, respectively, with full retention of the configuration of the stereocenters alpha to the CHNO(2)/C=N-SPh/C=O groups.
More Related Videos
06:00One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates
Published on: January 15, 2018
06:34Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides (CHIPS)
Published on: June 20, 2014
Related Concept Videos
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes
Nitrosation of Enols
Preparation of Aldehydes and Ketones from Nitriles and Carboxylic Acids
Reducing carboxylic acid derivatives like acyl chlorides (RCOCl), esters (RCO2R′), and nitriles (RCN) using milder aluminum hydride agents like lithium tri-tert-butoxyaluminum hydride [LiAlH(O-t-Bu)3] and diisobutylaluminum hydride [DIBAL-H] allows...
