265999-47-1Relevant articles and documents
Oxidative homologation of aldehydes to α-ketoaldehydes by using iodoform, o-iodoxybenzoic acid, and dimethyl sulfoxide
Zall, Andrea,Bensinger, Dennis,Schmidt, Boris
experimental part, p. 1439 - 1447 (2012/04/04)
An efficient three-step synthetic route to α-ketoaldehydes starting from aryl aldehydes is reported. The aldehydes were treated with iPrMgCl and iodoform to obtain β-diiodoalcohols, which were then oxidized with o-iodoxybenzoic acid at room temperature to the corresponding β-diiodoketones. Subsequent reaction of the β-diiodoketone to the α-ketoaldehyde occurred under oxygen transfer from dimethyl sulfoxide. These sensitive products were in situ cyclized with o-phenylenediamine to form the stable monosubstituted quinoxalines, which could be characterized and isolated easily. α-Ketoaldehydes are a versatile, highly reactive moiety for the synthesis of heterocyclic compounds. We investigated the transformation of aldehydes into α-ketoaldehydes via β-diiodoketone intermediates and finally applied the procedure to the synthesis of peptidic substrates. Copyright
Catalytic Hunsdiecker reaction and one-pot catalytic Hunsdiecker-Heck strategy: Synthesis of α,β-unsaturated aromatic halides, α- (dihalomethyl)benzenemethanols, 5-aryl-2,4-pentadienoic acids, dienoates and dienamides
Naskar, Dinabandhu,Roy, Sujit
, p. 1369 - 1377 (2007/10/03)
The reaction of α,β-unsaturated aromatic (or heteroaromatic) carboxylic acids with N-halosuccinimides (1 equiv.) and catalytic tetrabutylammonium trifluoroacetate (0.2 equiv.) in dichloroethane results in facile halodecarboxylation affording the corresponding (E)-halides in good to excellent yields. A similar reaction, but with 2 equiv. of N-halosuccinimides in acetonitrile-water (1:1 v/v) results in the exclusive formation of the corresponding α-(dihalomethyl)benzenemethanols. Furthermore, a one-pot strategy has been developed combining catalytic Hunsdiecker reaction (using tetrabutylammonium trifluoroacetate in dichloroethane) and Heck coupling (using palladium acetate/triethylamine/triphenylantimony/dichloroethane) for the synthesis of 5-aryl-2,4-pentadienoic acids, esters and amides in moderate to good yields. The natural product piperine and pipergualamine has been synthesized via the above route. Mechanistic and theoretical studies (via AM1 calculations) provide a useful insight into the mechanism of the present halodecarboxylation reaction, suggesting an ionic pathway involving the attack of the halogenium ion across the carbon-carbon double bond, triggering the elimination of carbon dioxide. (C) 2000 Elsevier Science Ltd.
