palladium(0)-catalyzed, Cu(I)-mediated synthetic route to trisubstituted olefins and conjugate dienes has been developed via oxo directing Liebeskind–Srogl cross-coupling reactions of gem-dihaloolefin-type α-oxo ketene dithioacetals with aryl and alkenylboronic acids. The synthetic protocol has demonstrated rare examples of transition-metal-promoted transformations of ketene dithioacetals, providing a novel route to
FeCl3·6H2O-Catalyzed Tandem Alkylation–Hydrolysis Reaction of Chain α-Oxo Ketene Dithioacetals with Alcohols: Efficient Synthesis of α-Alkylated β-Oxo Thioesters
A novel FeCl3·6H2O-catalyzed tandem Friedel–Crafts alkylation–hydrolysis reaction between chain α-oxo ketene dithioacetals and alcohols to afford α-alkylated β-oxo thioesters has been successfully developed. The reaction is efficient in the presence of catalyst loading as low as 30 mol% in MeCN at roomtemperature, and a wide variety of α-alkylated β-oxo thioesters are efficiently synthesized in good
Visible <scp>Light‐Induced</scp> [3+2] Annulation Reaction of Alkenes with Vinyl Azides: Direct Synthesis of Functionalized Pyrroles
作者:Ming Yang、Xin‐Yu Wang、Jie Wang、Yu‐Long Zhao
DOI:10.1002/cjoc.202300498
日期:2024.1.15
photocatalytic [3+2] annulation of alkenes with vinyl azides was developed under irradiation by visiblelight in the presence of organic dye photocatalysts. Broad substrate scope and high functional group tolerance were demonstrated by more than 50 examples. The reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free conditions without other
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.
Direct Synthesis of Highly Substituted 2-Cyclohexenones and Sterically Hindered Benzophenones Based on a [5C + 1C] Annulation
作者:Zhenqian Fu、Mang Wang、Ying Dong、Jun Liu、Qun Liu
DOI:10.1021/jo9013386
日期:2009.8.21
DMF at room temperature, highly substituted 2-cyclohexenones 3 were synthesized in high to excellent diastereoselectivities with high yields. On the basis of this strategy, stericallyhindered benzophenones 4 were conveniently prepared via the iodonation−aromatization of 2-cyclohexenones 3 with I2 in MeONa/MeOH basic medium. Furthermore, benzophenones 4 were also obtained directly from 1 and 2 following