1,4-Additions of arylboron, -silicon, and -bismuth compounds to α,β-unsaturated carbonyl compounds catalyzed by dicationic palladium(II) complexes
2008; International Union of Pure and Applied Chemistry; Volume: 80; Issue: 5 Linguagem: Inglês
10.1351/pac200880050807
ISSN1365-3075
AutoresYasunori Yamamoto, Takashi Nishikata, Norio Miyaura,
Tópico(s)Asymmetric Synthesis and Catalysis
ResumoAbstract An enantioselective synthesis of cyclic and acyclic β-aryl ketone and aldehydes via Pd(II)-catalyzed 1,4-addition of Ar- m [ m = B(OH) 2 , BF 3 K, Si(OMe) 3 , SiF 3 , BiAr 2 ] to α,β-unsaturated ketones or aldehydes is described. The catalytic cycle involves transmetallation between Ar- m and Pd complexes as a key process, the mechanism of which is discussed on the basis of characterization of the transmetallation intermediate and electronic effect of the substituents. The enantioselection mechanism and efficiency of a chiraphos ligand for structurally planar α,β-unsaturated ketones are discussed on the basis of the X-ray structure of the catalyst and results of density functional theory (DFT) computational studies on the model of coordination of the substrates to the phenylpalladium(II)/( S , S )-chiraphos intermediate.
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