Copper-Catalyzed Ring-Expansion/Thiolactonization<i>via</i>Azidation of Internal Olefinic C-H Bond under Mild Conditions
作者:Tenglong Guo、Quanbin Jiang、Zhengkun Yu
DOI:10.1002/adsc.201600675
日期:2016.11.3
A copper(I)‐catalyzed, (diacetoxyiodo)benzene [PhI(OAc)2]‐mediated ring‐expansion/thiolactonization of α‐oxo ketene dithioacetals was efficiently realized via azidation of the internal olefinic C−H bond with sodium azide under mild conditions. Sequential amination, ring‐expansion rearrangement, and thiolactonization occurred to form aminated thiolactones in the presence of acetic anhydride as the additive
α-Alkenoyl Ketene <i>S</i>,<i>S</i>-Acetal-Based Multicomponent Reaction: An Efficient Approach for the Selective Construction of Polyfunctionalized Cyclohexanones
作者:Yuhui Ma、Mang Wang、Dan Li、Bahargul Bekturhun、Jun Liu、Qun Liu
DOI:10.1021/jo900217g
日期:2009.4.17
A versatile multicomponent reaction based on the new four-carbon synthons alpha-alkenoyl ketene S,S-acetals 1 has been developed. This three-component reaction of readily available alpha-alkenoyl ketene S,S-acetals 1 with aldehydes 2 and active methylene compounds 3 proceeds smoothly in acidic medium (glacial acetic acid in tetrahydrofuran) to give various polyfunctionalized cyclohexanones 4, 5, and 6 in a highly regio- and diastereoselective manner with good to excellent yields. The reaction can tolerate a broad range of substituents in the three components involved and is proposed to proceed via a tandem Knoevenagel-intermolecular Michael-intramolecular Michael sequence. As an extension of the synthetic application of polyfunctionalized cyclohexanones obtained, unsymmetrical biaryls 7 were synthesized in almost quantitative yields by simple transformations of the corresponding cycloadducts 6.
Palladium-Catalyzed Cross-Coupling of Internal Alkenes with Terminal Alkenes to Functionalized 1,3-Butadienes Using CH Bond Activation: Efficient Synthesis of Bicyclic Pyridones
cross‐coupling of internal alkenes of α‐oxoketene dithioacetals with terminal alkenes has been successfully realized by palladium‐catalyzedCH bond activation, affording functionalized 1,3‐butadienes. Condensation of the resultant 1,3‐butadienes by diamines efficiently produced potentially bioactive bicyclic pyridone derivatives (see scheme).
DBSA-catalyzed Friedel–Crafts alkylation of cyclic ketene dithioacetals with alcohols in water
作者:Haifeng Yu、Peiqiu Liao
DOI:10.1016/j.tetlet.2016.05.062
日期:2016.6
A novel DBSA-catalyzed Friedel–Crafts alkylation of cyclic ketene dithioacetals, internal alkenes with highly nucleophilic carbon atom adjacent to the electron-withdrawing group, with alcohols in water has been developed. The reaction is efficient in the presence of catalyst loading as low as 10 mol % in water at reflux, and a wide range of alkylated ketene dithioacetals are synthesized in excellent