Asymmetric copper-catalyzed allylic alkylation between allyl bromides and alkyl Grignard reagents using a P-chiral monophosphorus ligand is described. A range of terminal olefins bearing tertiary or quaternary carbon centers were formed in good branched/linear selectivities and excellent enantioselectivities at copper loadings as low as 0.5 mol %.
Aryltriolborates as Air- and Water-Stable Bases for Wittig Olefination
作者:Wenhua Huang、Shuang-Hong Zhao、Ning Xu
DOI:10.1055/s-0034-1378919
日期:——
1-tris(hydroxymethyl)ethane, and aqueous tetrabutylammonium hydroxide. The aryltriolborates can be used as bases in Wittigreactions of aromatic aldehydes with all three types of phosphorus ylides: stabilized and semistabilized ylides can be generated at room temperature, and nonstabilizedylides at 120 °C (bath temperature). Tetrabutylammonium aryltriolborates have been synthesized in 37–66% yield by a one-pot
The palladium-catalyzed reaction of γ-silylated allyl acetates with water in the presence of CsF induces a previously unprecedented 1,2-shift of a substituent on silicon to produce allylsilanes in situ. The catalytic activity of the palladium increased when using an electron-poor phosphine ligand possessing fluorinated substituents. Further investigation of the reaction revealed that the approximate
N-Heterocyclic Carbene Derived Nickel-Pincer Complexes: Efficient and Applicable Catalysts for Suzuki-Miyaura Coupling Reactions of Aryl/Alkenyl Tosylates and Mesylates
作者:Jun-ichi Kuroda、Kiyofumi Inamoto、Kou Hiroya、Takayuki Doi
DOI:10.1002/ejoc.200900067
日期:2009.5
activities of NHC-derived nickel–pincercomplexes for the Suzuki–Miyauracouplingreactions of aryl/alkenyltosylates and mesylates are described. In the presence of a catalytic amount of nickelacycle 1a, a wide array of tosylates and mesylates reacted with several aryl- and alkenylboronic acids to afford the coupling products, generally in high yields. Fine tuning of the reaction conditions for each class