Sodium Phenoxide−Phosphine Oxides as Extremely Active Lewis Base Catalysts for the Mukaiyama Aldol Reaction with Ketones
作者:Manabu Hatano、Eri Takagi、Kazuaki Ishihara
DOI:10.1021/ol702052r
日期:2007.10.1
A highly efficient Mukaiyama aldolreaction between ketones and trimethylsilyl enolates catalyzed by sodium phenoxide-phosphine oxides as simple homogeneous Lewis base catalysts (0.5-10 mol %) was developed, which minimized competing retro-aldolreaction. For a variety of aromatic ketones and aldimines, aldol and Mannich-type products with an alpha-quaternary carbon center were obtained in good to
Carboboration‐Driven Generation of a Silylium Ion for Vinylic C−F Bond Functionalization by B(C
<sub>6</sub>
F
<sub>5</sub>
)
<sub>3</sub>
Catalysis
作者:Tetsuji Yata、Yoshihiro Nishimoto、Makoto Yasuda
DOI:10.1002/chem.202103852
日期:2022.2
B(C6F5)3-catalyzed reactions between fluoroalkenes and silyl ketene acetals gave vinylic C−F bond-functionalized products under mild and simple conditions. Carboboration reaction of fluoroalkenes generates an oxygen-stabilized silylium ion to facilitate the C−F bond cleavage. DFT and IBO studies were performed to clear the reaction mechanism. A comparative study of α-chloro or bromostyrenes demonstrated
Synthesis of (
<i>Z</i>
)‐β‐(Carbonylamino)alkenylindium through Regioselective
<i>anti</i>
‐Carboindation of Ynamides and Its Transformation to Multisubstituted Enamides
an anti-addition, which was supported by DFT calculations. The scope of substrates included various ynamides and silylated nucleophiles, such as silyl ketene acetals and silyl ketene imines. The transformation of synthesized alkenylindiums by iodination, radical coupling, and Pd-catalyzed cross-coupling successfully afforded trisubstituted enamines with high regio- and stereoselectivities.
Iridium-Catalyzed Enantioselective Allylic Substitution of Aliphatic Esters with Silyl Ketene Acetals as the Ester Enolates
作者:Xingyu Jiang、John F. Hartwig
DOI:10.1002/anie.201704354
日期:2017.7.17
Enantioselective allylic substitution with enolates derived from aliphatic esters under mild conditions remains challenging. Herein we report iridium‐catalyzed enantioselective allylation reactions of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon atom at the nucleophile moiety and a tertiary carbon atom at the electrophile moiety. Under relatively
Coupling Reaction of Enol Derivatives with Silyl Ketene Acetals Catalyzed by Gallium Trihalides
作者:Yoshihiro Nishimoto、Yuji Kita、Hiroki Ueda、Hiroto Imaoka、Kouji Chiba、Makoto Yasuda、Akio Baba
DOI:10.1002/chem.201602150
日期:2016.8.8
cross‐coupling reaction between enolderivatives and silyl ketene acetals catalyzed by GaBr3 took place to give the corresponding α‐alkenyl esters. GaBr3 showed the most effective catalytic ability, whereas other metal salts such as BF3⋅OEt2, AlCl3, PdCl2, and lanthanide triflates were not effective. Various types of enol ethers and vinyl carboxylates as enolderivatives are amenable to this coupling