Solvent-free condensations of ketones with malononitrile catalysed by methanesulfonic acid/morpholine system
作者:M. Góra、B. Kozik、K. Jamroży、M. K. Łuczyński、P. Brzuzan、M. Woźny
DOI:10.1039/b820901d
日期:——
The preparation of ylidenemalononitriles viaKnoevenagel condensations of ketones with malononitrile under solvent-free conditions is described. Good yields and short reaction time are the features observed with methanesulfonic acid (MSA)/morpholine used as the catalyst. The wide applicability of the protocol is shown by the fact that not only unconjugated, but also aryl-alkyl ketones gave satisfactory
Visible-Light-Mediated Intermolecular Radical Conjugate Addition for the Construction of Vicinal Quaternary Carbon Centers
作者:Lei Li、Lili Fang、Weiping Wu、Jin Zhu
DOI:10.1021/acs.orglett.0c01724
日期:2020.7.17
The visible light-driven organophotoredox catalysis is reported for the construction of vicinal quaternary carbon centers. Intermolecular conjugateaddition of alkyl radicals, derived from 2,2-disubstituted dihydroquinazolinones, to Michael acceptors under blue light irradiation and rhodamine B catalysis allows the facile assembly of diverse, vicinal secondary/quaternary, tertiary/quaternary, and
using diverse electrophilic double bonds. Ethyl radical derived from Et3B under air cleaved the C–Te bond of 2 to generate α-alkoxy bridgehead radical I, which reacted with cycloalkenones, cycloalkylidenemalononitriles, allyl halides, and imines at or below ambient temperature. These intermolecular reactions from O,Te-acetal 2 were mild and versatile, and were superior to those of O,Se-acetal 1 in
Et 3 B / O 2介导的O,Te-乙缩醛2的自由基偶联反应是通过使用各种亲电双键进行的。空气中从Et 3 B衍生的乙基在2的C-Te键上断裂,生成α-烷氧基桥头基I,在室温或低于环境温度下,它与环烯酮,环烷基亚甲基丙二腈,烯丙基卤和亚胺反应。O,Te-乙缩醛2的这些分子间反应温和,多用途,优于O,Se-乙缩醛1的分子间反应在效率和基材范围方面。总共描述了14个新的偶联反应和9个改进的偶联反应,所有这些反应都实现了将功能化碳单元安装在三恶唑金刚烷的空间位阻桥头位置。
Application of α-Alkoxy Bridgehead Radical for Coupling of Oxygenated Carbocycles
作者:Daisuke Urabe、Hiroki Yamaguchi、Masayuki Inoue
DOI:10.1021/ol201758a
日期:2011.9.16
developed. An α-alkoxy bridgehead radical was employed as the key reactive intermediate due to its potent reactivity, minimum steric interaction, and predestined stereochemical outcome. The radical of the trioxadamantane structure, generated from the O,Se-acetal, was reacted with electron-deficient cyclicolefins of various ringsizes. Intermolecular formation of sterically congested linkages between
An easy protocol for the domino synthesis of diversely functionalized spirocarbocycles and their biological evaluation
作者:SELVARANGAM E KIRUTHIKA、PARAMASIVAN T PERUMAL、C BALACHANDRAN、S IGNACIMUTHU
DOI:10.1007/s12039-013-0560-1
日期:2014.1
reported. This consists of a series of steps including Knoevenagel condensation followed by intermolecular vinylogous Michael addition and intramolecular cyclization. The synthesized compounds were evaluated for their antimicrobial activity and the compounds exhibited moderate to excellent activities. Synopsis: A base catalyzed domino reaction for the synthesis of spirocarbocycles in excellent yields