The asymmetric tandem oxa-Michael-aldol reaction of salicylic aldehyde derivatives with α,β-unsaturated aldehydes catalyzed by a chiral amine/chiral acid organocatalytic system was investigated. The organocatalytic system of (S)-diphenylpyrrolinol trimethylsilyl ether with chiralshiftreagent (S)-Mosher acid presented a synergistic effect in the improvement of reaction performance and offered an efficient
研究了水杨醛衍生物与手性胺/手性酸有机催化体系催化的α,β-不饱和醛的不对称串联氧杂-迈克尔-阿尔道反应。(S)-二苯基吡咯啉三甲基甲硅烷基醚与手性转移剂(S)-Mosher酸的有机催化体系在提高反应性能方面具有协同作用,并在转化中提供了有效的空间效应。串联的oxa-Michael-aldol反应以高收率(最高90%)和优异的ee值(最高99%)进行,得到相应的色烯衍生物。还通过1 H NMR研究了原位形成的手性铵盐的结构及其相应的机理。
Catalytic Enantioselective Domino Oxa-Michael/Aldol Condensations: Asymmetric Synthesis of Benzopyran Derivatives
The first direct organocatalyticasymmetricdomino oxa-Michael/aldol condensation reaction is presented. The unprecedentedly simple, chiral, pyrrolidine-catalyzed asymmetricdominoreactions between salicylic aldehyde derivatives and alpha,beta-unsaturated aldehydes proceed with high chemo- and enantioselectivities to give the corresponding chromene-3-carbaldehyde derivatives in high yields and with
One-pot approach to chiral chromenesvia enantioselective organocatalytic domino oxa-Michael–aldol reaction
作者:Hao Li、Jian Wang、Timiyin E-Nunu、Liansuo Zu、Wei Jiang、Shaohua Wei、Wei Wang
DOI:10.1039/b611502k
日期:——
A highly enantioselective (S)-diphenylpyrrolinol triethylsilyl ether promoted tandem oxa-Michaelâaldol reaction of α,β-unsaturated aldehydes with salicylaldehydes has been developed; the method affords one-pot access to chiral and synthetically useful chromenes in high yields and high enantioselectivities from readily available compounds.
Recyclable Tertiary Amine Modified Diarylprolinol Ether as Aminocatalyst for the Sequential Asymmetric Synthesis of Functionalized Cyclohexanes and Chromenes
β-unsaturated aldehydes with recyclable tertiary amine-modified diarylprolinol silylether 3d as an effective organocatalyst, which results in the formation of chiral chromenes with good enantioselectivities (up to 94 % ee). UV/Vis and CD spectroscopy provide a cross-validation method to elucidate the slight difference between electron-withdrawing 3d and diphenylprolinol silylether 3a, which can give
β-硝基丙烯酸酯、醛、甲苯硫醇和 2-(二乙氧基磷酰基)丙烯酸乙酯的一锅有机催化 Hayashi 顺序反应 (HSR) 允许合成几乎立体异构纯、高度官能化的多取代环己烷,具有非常高的非对映选择性和对映选择性(高达 > 99 % ee)。一锅合成包括叔胺修饰的二芳基脯氨醇甲硅烷基醚介导的不对称迈克尔反应、多米诺迈克尔反应/霍纳-沃兹沃思-埃蒙斯反应和磺胺-迈克尔反应。此外,我们还展示了一种改进的方案,用于水杨醛与 α,β-不饱和醛与可回收的叔胺改性二芳基脯氨醇甲硅烷基醚 3d 作为一种有效的有机催化剂,进行多米诺 oxa-Michael/aldol 反应,这导致形成具有良好对映选择性(高达 94% ee)的手性色烯。UV/Vis 和 CD 光谱提供了一种交叉验证方法来阐明吸电子 3d 和二苯基脯氨醇甲硅烷基醚 3a 之间的细微差异,这可以间接证明上述转化中 3d 对映选择性诱导的增强。
Multifaceted Domino Knoevenagel‐Cyclization Reactions; Four Movements for 2
<i>H</i>
‐Chromenes and Chromans
作者:Sándor Balázs Király、László Tóth、Tibor Kovács、Attila Bényei、Erika Lisztes、Balázs István Tóth、Tamás Bíró、Attila Kiss‐Szikszai、Katalin E. Kövér、Attila Mándi、Tibor Kurtán
DOI:10.1002/adsc.202300083
日期:——
amine or ether side-chain was carried out to produce four series of chiral condensed heterocycles representing four novel skeletons and exhibiting antiproliferative activity. The cyclization step occurred with four different mechanisms: a concerted intramolecular hetero Diels-Alder reaction (IMHDA), a stepwise polar [2+2] cycloaddition, a [1,5]-hydride shift-6-endo cyclization or a multi-step nitro hetero