Aromatic heteroannulation via metalation-cyclization of N-acyl-2-chlorobenzenesulfonamides and N-acylbenzenesulfonamides
摘要:
N-Acyl-2-chlorobenzenesulfonamides 7a-d undergo competitive metal-halogen exchange and or alpha-deprotonation reactions when treated sequentially with sodium hydride and n-butyllithium. The o-lithio intermediates derived from metal-halogen exchange and ortho-deprotonation undergo cyclization to afford 3-substituted 1,2-benzisothiazole 1,1-dioxides 10a-d and 3-substituted 7-chloro-1,2-benzisothiazole 1,1-dioxides 14a-d, respectively. Reaction time-temperature data show evidence for the slow conversion of the lateral dianion of N-acetyl-2-chlorobenzenesulfonamide (7a) to the corresponding N,ortho-dialkali salt. 1,2-Benzisothiazole 1,1-dioxides 14a-d were obtained in good yield and free from products resulting from metal-halogen exchange by treatment of sulfonamides 7a-d with 2 equiv of LDA in THF. In the presence of 2 equiv of LDA, N-acylbenzenesulfonamides devoid of or containing only weakly acidic alpha-hydrogens undergo alpha-deprotonation-cyclization to afford the respective 1,2-benzoisothiazole 1,1-dioxides.
CoII/Box‐catalyzed [Box=bis(oxazoline)] enantioselective addition of potassium allyltrifluoroborate to cyclic ketimines was developed, providing the corresponding chiral α‐tertiary amines in high yields and with good enantioselectivity values. Alkoxycarbonyl‐ and alkyl‐substituted saccharin‐derived ketimines are suitable substrates for this allylation reaction. The product can be converted to complex molecules
开发了Co II / Box催化的[Box =双(恶唑啉)]烯丙基三氟硼酸钾对环酮亚胺的对映选择性加成,提供了高收率和良好对映选择性值的相应手性α-叔胺。烷氧羰基和烷基取代的糖精衍生的酮亚胺是该烯丙基化反应的合适底物。该产品可以通过几个简单的步骤转化为复杂的分子,包括MK-0371的前体,它是一种驱动蛋白纺锤体蛋白抑制剂。另外,该催化体系显示出强烈的正非线性效应。
Spiro indane-based phosphine–oxazoline ligands for palladium-catalyzed asymmetric arylation of cyclic N-sulfonyl imines
作者:Zhongxuan Qiu、Yanshun Li、Zhenqing Zhang、Dawei Teng
DOI:10.1007/s11243-019-00329-z
日期:2019.10
Palladium complexes of indane-based phosphine–oxazoline ligands with a spirocarbon stereogenic center were examined for asymmetric addition of arylboronic acids to cyclic N-sulfonyl imines. Excellent reaction activities (up to 99% yield) and enantioselectivities (up to 99% ee) were obtained with a broad scope of substrate.
Highly Enantioselective Construction of Fluoroalkylated Quaternary Stereocenters via Organocatalytic Dehydrated Mannich Reaction of Unprotected Hemiaminals with Ketones
作者:Sheng Zhang、Lijun Li、Yanbin Hu、Yanan Li、Yu Yang、Zhenggen Zha、Zhiyong Wang
DOI:10.1021/acs.orglett.5b02514
日期:2015.10.16
organocatalytic asymmetric dehydrated Mannich reaction of fluoroalkyl hemiaminals with ketones is reported. In this Mannich reaction, previously less explored aryl ketones showed great reactivity. By virtue of this efficient method, a wide range of biologically active β-amino ketones were directly obtained. More importantly, two different intermediates involved in the reaction were detected and identified by 19F
报道了氟代烷基半缩醛与酮的一般有机催化不对称脱水曼尼希反应。在该曼尼希反应中,以前较少探索的芳基酮显示出很高的反应活性。通过这种有效的方法,直接获得了广泛的生物活性β-氨基酮。更重要的是,通过19 F NMR和HRMS分析检测并鉴定了参与反应的两种不同中间体。此外,通过生物活性的氟烷基β-氨基醇的合成证明了产物的合成效用。
The preparation of 3-substituted 1,2-benzisothiazole 1,1-dioxides from lithiated intermediates or grignard reagents and methyl 2-(aminosulfonyl)benzoate
作者:S. Patrick Dunn、Laela M. Hajiaghamohseni、Sara B. Lioi、Michelle A. Meierhoefer、Matthew J. Walters、Charles F. Beam
DOI:10.1002/jhet.5570410225
日期:2004.3
A polylithiated β-ketoester, β-diketone, or β-ketoamide was condensed-cyclized with lithiatedmethyl2-(aminosulfonyl)benzoate, to afford new 3-substituted 1,2-benzisothiazole 1,1-dioxides. Some Grignard or organolithium reagents were also condensed-cyclized with methyl2-(aminosulfonyl)benzoate to give 3-substituted 1,2-benzisothiazole 1,1-dioxides.
enantioselective Pd-catalyzed asymmetricallylic substitution cascade of cyclic N-sulfonylimines with an accompanying asymmetric desymmetrization has been developed for the construction of fused tetrahydroindole derivatives bearing two chiral centers. Mechanistic studies confirmed that the cascade reaction proceeds by initial allylicalkylation and subsequent allylic amination. The first alkylation is a chirality-control