An Aminocatalyzed Stereoselective Strategy for the Formal α-Propargylation of Ketones
作者:Igor D. Jurberg
DOI:10.1002/chem.201701433
日期:2017.7.21
A two‐step reaction sequence is described for the asymmetric formal α‐propargylation of ketones. This approach takes advantage of an aminocatalyzed conjugateaddition of ketones to alkylidene isoxazol‐5‐ones, followed by a controlled nitrosative degradation event. The target compounds can be accessed in broad scope, in moderate to good yields, perfect diastereocontrol and good to excellent enantioselectivity
Rh(III)-Catalyzed Regioselective Annulations of 3-Arylisoxazolones and 3-Aryl-1,4,2-dioxazol-5-ones with Propargyl Alcohols: Access to 4-Arylisoquinolines and 4-Arylisoquinolones
The Rh(III)-catalyzed dual directing group assisted C–H activation/annulation of 3-arylisoxazolones with propargyl alcohols has been developed, which expands the application scope of isoxazolones in organic synthesis. This protocol also worked well with 3-aryl-1,4,2-dioxazol-5-ones to produce synthetically and biologically important 4-arylisoquinolones.
Rh(III)-Catalyzed [4 + 2] Annulation of 3-Aryl-5-isoxazolone with Maleimides or Maleic Ester
作者:Ting Wan、Chao Pi、Yangjie Wu、Xiuling Cui
DOI:10.1021/acs.orglett.0c02283
日期:2020.8.21
The Rh(III)-catalyzed [4 + 2] annulation of 3-aryl-5-isoxazolones with maleimides or maleic ester has been developed, which gives synthetically important 3,4-dihydroisoquinoline derivatives in good to excellent yields. This facile protocol can tolerate a variety of functional groups, and CO2 was produced as the predominant byproduct. Notably, a C–C bond and a C–N bond were formed simultaneously. This
Isoxazol-5(4H)one Derivatives as PTP1B Inhibitors Showing an Anti-Obesity Effect
作者:Bhooshan Kafle、Nilkanth G. Aher、Deegendra Khadka、Hwangseo Park、Hyeongjin Cho
DOI:10.1002/asia.201100154
日期:2011.8.1
prepared in a day by using the present protocol. The library compounds thus obtained were examined for their inhibitory activities against PTP1B. Among them, compound C3 was the most potent inhibitor of PTP1B with an IC50 of 2.3 μM. The in vivo effect of C3 was also examined in an obesity‐prone mouse strain. Diet‐induced obese (DIO)/diabetic mice were divided into two groups and each group was fed a
Cooperative Catalysis with Coupled Chiral Induction in 1,3-Dipolar Cycloadditions of Azomethine Ylides
作者:Alberto Cayuelas、Olatz Larrañaga、Verónica Selva、Carmen Nájera、Takahiko Akiyama、José M. Sansano、Abel de Cózar、José I. Miranda、Fernando P. Cossío
DOI:10.1002/chem.201801433
日期:2018.6.7
3‐Dipolar cycloadditions (1,3‐DC) between imino esters (as precursors of N‐metallated azomethine ylides) and π‐deficient alkenes are promoted by cooperative asymmetric Lewis acid/Brønsted base catalysis. The components of these catalytic pairs are silver saltsderivedfrom enantiopure commercially available BINOL‐based phosphoric acids and Cinchona alkaloids. Chiral phosphoric silver(I) salts promote