Ultrasound-Promoted Synthesis of Arylzinc Compounds Using Zinc Powder and Their Application to Palladium(0)-Catalyzed Synthesis of Multifunctional Biaryls
Novel Rh(I)-Catalyzed Reaction of Arylzinc Compounds with Methyl Halides
作者:Kabir M. Hossain、Kentaro Takagi
DOI:10.1246/cl.1999.1241
日期:1999.11
The cross-coupling reactions of arylzinc compounds with methyl iodide or substituted methyl halides like benzyl bromides took place smoothly by the catalysis of Rh(I)-dppf complex.
Addition of arylzincs to aldehydes was achieved by making use of the novel transmetallation of arylzincs into Cr3+ compounds. Various α-substituted benzyl alcohols or 3-substituted 1(3H)-isobenzofuranones, containing reactive functional groups, were synthesized in good yields. Me3SiCl exerted beneficial effects on the reaction.
Nucleophilic Additions of Arylzinc Compounds to Aldehydes Mediated by CrCl<sub>3</sub>: Efficient and Facile Synthesis of Functionalized Benzhydrols, 1(3<i>H</i>)-Isobenzofuranones, Benzyl Alcohols, or Diaryl Ketones
benzhydrols 4a-f in good yields. From arylzinc compounds 1a,b, 3-aryl-1(3H)-isobenzofuranones 3a-f were given by the CrCl(3)-mediated reaction with arylaldehydes 2a-f. Diaryl ketones 5a-e were obtained in good yields by the addition of excess amount of benzaldehyde as an oxidant to the resulting solution after the CrCl(3)-mediated reaction between arylzinc compounds 1c-g and arylaldehydes 2b,g was completed
3-Diphenylphosphino-2-(diphenylphoshino)methyl-2-methylpropyl acetate acted as an efficient ligand for a Rh catalyst, achieving cross-coupling between arylzinc compounds bearing electron-withdrawing groups and alkyl electrophiles. The beneficial effect of the tripodal ligand and such aryl nucleophiles was discussed with regard to the specificity of the Rh catalysis.