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|Type:||Artigo de periódico|
|Title:||Stereoselective Synthesis Of Unsymmetrical β,β-diarylacrylates By A Heck-matsuda Reaction: Versatile Building Blocks For Asymmetric Synthesis Of β,β-diphenylpropanoates, 3-aryl-indole, And 4-aryl-3,4-dihydro- Quinolin-2-one And Formal Synthesis Of (-)-indatraline|
|Abstract:||β,β-Disubstituted R,β-unsaturated esters may serve as valuable derivatives for the preparation of other highly functionalized systems found in many natural products and marketed drugs. The stereoselective synthesis of unsymmetrical β,β-diarylacrylate compounds possessing two similar aromatic groups remains a substantial challenge. A simple and convenient stereoselective protocol for the preparation of β,β- disubstituted acrylates via a Heck-Matsuda reaction is reported. Good to high yields were accomplished by a "ligand-free" Pd-catalyzed arylation reaction of cinnamate esters with arenediazonium tetrafluoroborates. Both electron-deficient and electron-rich arenediazonium salts could be employed as arylating reagents, and cinnamate esters were generally more reactive when substituted with an electron-donating group. The overall methodology is highly stereoselective, and this attribute was taken advantage of in the asymmetric Cu-catalyzed 1,4 reduction reaction to provide β,β-diarylpropanoates in high enantioselectivities. The synthesis of a 3-aryl indole and a chiral 4-aryl-2-quinolone from β,β-diarylacrylates was achieved by cyclization in the presence of a diphosphine ligated CuH catalyst. A convenient route for the asymmetric formal synthesis of the psychoactive compound (-)-Indatraline is also presented. © 2010 American Chemical Society.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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