Mild Electrophilic Trifluoromethylation of β-Ketoesters and Silyl Enol Ethers with 5-Trifluoro Methyldibenzothiophenium Tetrafluoroborate
作者:Jun-An Ma、Dominique Cahard
DOI:10.1021/jo034881e
日期:2003.10.1
to excellent yields. In a second approach, 5-trifluoromethyldibenzothiophenium tetrafluoroborate and tetrabutylammonium difluorotriphenylstannate were used for efficient electrophilic trifluoromethylation of various silyl enolethers leading to the corresponding alpha-trifluoromethyl ketones in good to high yields.
Phosphoramidites Are Efficient, Green Organocatalysts for the Michael Reaction. Mechanistic Insights into the Phosphorus-Catalyzed Michael Reaction of Alkynones and Implications for Asymmetric Catalysis
作者:Robert B. Grossman、Sébastien Comesse、Ravindra M. Rasne、Kazuyuki Hattori、Matthew N. Delong
DOI:10.1021/jo026425g
日期:2003.2.1
Hexamethylphosphorous triamide (HMPT) and other phosphoramidites and phosphites have been found to be efficient catalysts for the Michael reaction of alkenones and alkynones with malonates, (x-cyano, esters, beta-keto esters, and nitro compounds. The relatively nontoxic, easily hydrolyzed HMPT catalyzes the Michael reaction within seconds at room temperature in the absence of a solvent, and the reaction is worked up simply by removing the catalyst in vacuo. The Michael reactions of alkynones, unlike those of alkenones, are shown to be irreversible. The implications for asymmetric catalysis are discussed.
Hypervalent Iodine(III) Reagents with Transferable Primary Amines: Structure and Reactivity on the Electrophilic α-Amination of Stabilized Enolates
作者:Diogo L. Poeira、Ana Cláudia R. Negrão、Hélio Faustino、Jaime A. S. Coelho、Clara S. B. Gomes、Pedro M. P. Gois、M. Manuel B. Marques
DOI:10.1021/acs.orglett.1c04312
日期:2022.1.21
A new family of hypervalentiodine reagents containing transferable primary amine groups is described. Benziodoxolone-based reagents were synthesized on the gram-scale through operationally simple reactions in up to quantitative yields. These bench-stable solids were characterized by X-ray analysis and successfully employed in the α-amination of indanone-based β-ketoesters in up to 83% yield. Mechanistic
描述了包含可转移伯胺基团的新系列高价碘试剂。苯并氧唑酮类试剂通过操作简单的反应以高达定量的产率在克级合成。这些工作稳定的固体通过 X 射线分析进行了表征,并成功用于茚满酮基 β-酮酯的 α-胺化,产率高达 83%。机理研究表明了一种涉及亲电子胺的取代机理。
Highly Enantioselective Catalytic Fluorination and Chlorination Reactions of Carbonyl Compounds Capable of Two-Point Binding