4436-87-7Relevant academic research and scientific papers
Zinc(II)-catalyzed addition of grignard reagents to ketones
Hatano, Manabu,Ito, Orie,Suzuki, Shinji,Ishihara, Kazuaki
supporting information; experimental part, p. 5008 - 5016 (2010/10/04)
(Figure presented) The addition of organometallic reagents to carbonyl compounds has become a versatile method for synthesizing tertiary and secondary alcohols via carbon-carbon bond formation. However, due to the lack of good nucleophilicity or the presence of strong basicity of organometallic reagents, the efficient synthesis of tertiary alcohols from ketones has been particularly difficult and, thus, limited. We recently developed highly efficient catalytic alkylation and arylation reactions to ketones with Grignard reagents (RMgX: R = alkyl, aryl; X = Cl, Br, I) using ZnCl2, Me3SiCH 2MgCl, and LiCl, which effectively minimize problematic side reactions. In principle, RMgBr and RMgI are less reactive than RMgCl for the addition to carbonyl compounds. Therefore, this novel method with homogeneous catalytic ZnCl2·Me3SiCH2MgCl·LiCl is quite attractive, since RMgBr and RMgI, which are easily prepared and/or commercially available, like RMgCl, can be applied successfully. As well as ketones and aldehydes, aldimines were effectively applied to this catalysis, and the corresponding secondary amines were obtained in high yield. With regard to mechanistic details concerning β-silyl effect and salt effect, in situ-prepared [R(Me3SiCH2)2Zn] -[Li]+[MgX2]m[LiCl]n (X = Cl/Br/I) is speculated to be a key catalytic reagent to promote the reaction effectively. The simplicity of this reliable ZnCl2·Me 3SiCH2MgCl·LiCl system in the addition of Grignard reagents to carbonyl compounds might be attractive for industrial as well as academic applications.
AgAsF6 as safe alternative to AgClO4 for generating cationic zirconocene species: Utilities in Lewis acid-promoted selective C---C bond forming reactions
Suzuki, Keisuke,Hasegawa, Takayuki,Imai, Takahiro,Maeta, Hideki,Ohba, Shigeru
, p. 4483 - 4494 (2007/10/02)
For generating cationic zirconocene species that are useful for organic synthesis, AgAsF6 proved to be an efficient catalyst that serves as a safe alternative to AgClO4. Scope and limitation is discussed on this new catalyst in the processes including (1) alkyl/alkenyl transfer reaction from organozirconocene chloride to aldehyde, (2) two- and four-carbon homologation of aldehyde, (3) dual synthetic methods of 1,3-dienes from aldehydes/ketones via 1,3-bimetallic species, and (4) three-component alkylative cycloaddition via o-quinodimethane species.
Exploring the Reactivity of Alkenes Bearing Silicon and/or Tin in the Hydroxyl-Directed Hydrogenation. A Diastereoselective Synthesis of Heterobimetallic Compounds
Lautens, Mark,Zhang, C. H.,Goh, Betty Jane,Crudden, Cathleen M.,Johnson, Marc J. A.
, p. 6208 - 6222 (2007/10/02)
The hydroxyl-directed hydrogenation of (E)- and (Z)-γ-hydroxy vinylstannanes and silanes has been studied in the presence of (dppb)Rh(NBD)BF4 (1).Efficient routes to γ-hydroxy stannanes and silanes vave been developed.Diastereoselectivities from 60 to >50
Grignard-type Addition of Alkenyl- and Alkylzirconocene Chloride to Aldehyde: Remarkable Catalytic Acceleration Effect of AgClO4
Maeta, Hideki,Hashimoto, Takeshi,Hasegawa, Takayuki,Suzuki, Keisuke
, p. 5965 - 5968 (2007/10/02)
Nucleophilic addition of alkenylzirconocene chloride to aldehyde, which is ordinarily a slow reaction, is remarkably accelerated by a catalytic amount of AgClO4.The rate acceleration effect is also valid for the alkyl congener, Cp2Zr(Cl)R.
