Triethylgallium deprotonated cyclic and acyclicketones at 125-175 degrees C without forming carbonyl addition products, and the resulting gallium enolates underwent facile C-benzoylation and an aldol reaction. Unsymmetrical ketones were preferentially enolized at the methylene moiety, which was under kinetic control. [reaction: see text]
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Trisubstituted Olefins, α,β-Unsaturated Ketones and Imines with Chiral Benzylic Substituted P,N Ligands
作者:Wei-Jing Lu、Yun-Wei Chen、Xue-Long Hou
DOI:10.1002/adsc.200900618
日期:2010.1.4
The benzylic substituted P,N ligands, diphosphinobenzyloxazolines, showed their high catalytic activity as well as asymmetric induction in the iridium‐catalyzed asymmetric hydrogenation of unfunctionalized alkenes, α,β‐unsaturated esters, allyl alcohols, α,β‐unsaturated ketones, and imines, providing the corresponding chiral products in high ee with high conversion.
In the presence of catalytic amounts of GaCl3 (10 mol%) and 2,6-di(t-butyl)-4-methylpyridine (10 mol%), five- or six-membered ring ketones possessing α,α′-disubstituents are ethenylated at the α-carbon with triethylsilylethyne at 180 °C. The roles of the base are to inhibit decomposition of the products and to promote protodegallation of the organogallium intermediates.
在催化量的 GaCl3(10 摩尔%)和 2,6-二(叔丁基)-4-甲基吡啶(10 摩尔%)存在下,具有δ,δ′-二取代基的五元或六元环酮在 180 °C 下与三乙基硅基乙炔在δ-碳处发生乙烯基化反应。碱的作用是抑制产物的分解和促进有机镓中间体的原降解。
Selective catalytic synthesis of α-alkylated ketones and β-alkylated secondary alcohols <i>via</i> hydrogen-borrowing
作者:Md. Bakibillah、Sahin Reja、Kaushik Sarkar、Deboshmita Mukherjee、Rajesh Kumar Das
DOI:10.1039/d3nj02295a
日期:——
were shown to be efficient catalysts for α-alkylation of ketones and β-alkylation of secondary alcohols with primary alcohols in the presence of a catalytic amount of the Cp*Ir(III) catalyst and tBuOK in toluene at 110 °C via hydrogen-borrowing and produced substituted ketone products in good to excellent yields. This new C–C bond-formingreaction needs very small amounts of catalyst and base and produces
制备了由吡啶甲酰胺基部分支持的一组三种Ir-( III )配合物。这些络合物被证明是酮的 α-烷基化和仲醇与伯醇的 β-烷基化的有效催化剂,在催化量的 Cp*Ir( III ) 催化剂和t BuOK 的存在下,在甲苯中于 110 °C下通过借氢并以良好至优异的产率生产取代酮产品。这种新的 C-C 键形成反应需要非常少量的催化剂和碱,并且仅产生 H 2 O 作为副产物,使其成为一种有吸引力且环保的方案,可实现酮衍生物的“绿色”合成。
Palladium single-atom catalyst supported on ceria for α-alkylation of ketones with primary alcohols
supported on cubic CeO2 was prepared by simple impregnation, which exhibited excellent catalytic performance in α-alkylation of ketones with primary alcohols even under a low catalyst and base usage. The scope of the reaction was extended to various aromatic/aliphatic ketones and alcohols under the optimal catalytic system.
在此,通过简单的浸渍制备了负载在立方 CeO 2上的高活性和分散的单原子钯,即使在低催化剂和碱用量的情况下,它在酮与伯醇的 α-烷基化反应中也表现出优异的催化性能。在最佳催化体系下,反应范围扩展到各种芳香族/脂肪族酮和醇。