Visible light-mediated oxidative quenching reaction to electron-rich epoxides: highly regioselective synthesis of α-bromo (di)ketones and mechanism study
作者:Lin Guo、Chao Yang、Lewei Zheng、Wujiong Xia
DOI:10.1039/c3ob41245h
日期:——
A novel and simple procedure was developed for the regioselective synthesis of α-bromo (di)ketones from electron-rich epoxides viavisiblelightphotoredoxcatalysis. Through optimization of solvent and light source, the reaction can be rapidly achieved under mild conditions. Moreover, the possible reaction mechanism was proposed and further supported by control experiments.
The Enantioselective, Organocatalyzed Diels-Alder Reaction of 2-Vinylindoles with α,β-Unsaturated Aldehydes: An Efficient Route to Functionalized Tetrahydrocarbazoles
Prolinol catalysts: A highly enantio‐ and diastereoselective prolinol‐catalyzedDiels–Alderreaction of 2‐vinylindoles and α,β‐unsaturated aldehydes is developed (see scheme). This methodology allows the development of further applications of prolinols in asymmetric synthesis. The resulting densely functionalized enantiomerically pure tetrahydrocarbazoles are useful in the total synthesis of natural
bis(4-bromophenyl) derivative can be readily lithiated by the action of n-butyllithium in diethyl ether. The corresponding 4-trimethylsilyl and 4-methylthio derivatives were obtained by quenching the dilithio derivative with trimethylsilyl chloride and dimethyl disulfide, respectively. The Buchwald–Hartwig amination of the bromide with diphenylamine afforded the diphenylamino derivative in a good yield. Crystallographic
作为关键步骤,菲-9,10-二酮与两当量的亚苄基三苯基膦反应制备了一系列2,3-二苯基菲[9,10-b]呋喃。双(4-溴苯基)衍生物可以通过正丁基锂在乙醚中的作用容易地锂化。通过分别用三甲基甲硅烷基氯和二甲基二硫醚淬灭二锂衍生物,获得相应的 4-三甲基甲硅烷基和 4-甲硫基衍生物。溴化物与二苯胺的 Buchwald-Hartwig 胺化以良好的产率得到二苯氨基衍生物。母体二苯基衍生物的晶体学分析表明,菲呋喃部分具有轻微扭曲的类螺旋结构,该化合物在晶体中形成柱状堆积。菲呋喃在 CH2Cl2 和固态中均显示出强烈的蓝色荧光。它们的电化学性质显然表明呋喃具有高 HOMO 能级,正如密度泛函预测的那样...
Chemical structure and sweet taste of isocoumarin and related compounds. IX.
Structural modification of the phenyl moiety (A moiety) of β-(3-hydroxy-4-methoxyphenyl) ethylbenzene (I), which constitute an essential part of phyllodulcin molecules, was attempted to make the relationship between structure and sweet taste clearer. Twenty-four derivatives of A moiety of I were synthesized, the compound (II, IV, V, VI, X, XXII, XXIII, and XXVI) revealed sweet taste and the other compounds were tasteless. On the basis of these data, the taste of these compounds were discussed in connection with the stereochemical hindrance effect of substituents.
Chiral Imidodiphosphoric Acid-Catalyzed Highly Diastereo- and Enantioselective Synthesis of Poly-Substituted 3,4-Dihydro-2<i>H</i>-pyrans: [4 + 2] Cycloadditions of β,γ-Unsaturated α-Ketoesters and 3-Vinylindoles
Imidodiphosphoric acids were employed to catalyze inverse-electron-demand hetero-Diels–Alder reaction of β,γ-unsaturatedα-ketoesters and 3-vinylindoles. A series of optically active 3,4-dihydro-2H-pyran derivatives with three contiguous stereogenic centers was synthesized in excellent yields (70–99%), diastereoselectivities (>20:1), and enantioselectivities (73–99%). The resulting indole containing