expedient method was demonstrated for the synthesis of 3‐alkenyl‐3‐amino‐2‐oxindoles from readily available propargylic alcohols and isatin imines in the presence of BF3 ⋅ Et2O as a catalyst under open‐air atmosphere. The above reaction was time‐dependent and further extended to the one‐pot synthesis of highly substituted spiro‐indeneindolones via 1,3‐amino group migration/Friedel‐Crafts cyclization. This
Control of N-Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole-γ-Amino Acid Derivatives
作者:Xiang-Yu Chen、Jia-Wen Xiong、Qiang Liu、Sun Li、He Sheng、Carolina von Essen、Kari Rissanen、Dieter Enders
DOI:10.1002/anie.201708994
日期:2018.1.2
A strategy to control the switch between a non‐cycloaddition reaction and a cycloaddition reaction of enals, using N‐heterocyclic carbene (NHC) catalyisis, has been developed. The new scalable protocol leads to γ‐amino‐acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities by homo‐Mannich reactions of enals and isatin‐derived ketimines. By simply changing the
Dual Behavior of Isatin-Based Cyclic Ketimines with Dicarbomethoxy Carbene: Expedient Synthesis of Highly Functionalized Spirooxindolyl Oxazolidines and Pyrrolines
作者:T. Rajasekaran、G. Karthik、B. Sridhar、B. V. Subba Reddy
DOI:10.1021/ol400287q
日期:2013.4.5
devised for the synthesis of a wide range of spirooxindolyl oxazolidines via an intermolecular 1,3-dipolarcycloaddition of carbonyl ylides generated from dimethyl diazomalonate and aromatic aldehydes, with cyclic ketimines using 5 mol % of Rh2(OAc)4 under mild conditions. Similarly, highly functionalized spirooxindolyl pyrrolines have also been prepared through1,3-dipolarcycloaddition of azomethine
Rongalite-induced transition-metal and hydride-free reductive aldol reaction: a rapid access to 3,3′-disubstituted oxindoles and its mechanistic studies
3′-disubstituted oxindoles from isatin derivatives using rongalite. In this protocol, rongalite plays a dual role as a hydride-free reducing agent and a C1 unit donor. This transitionmetal-free method enables the synthesis of a wide range of 3-hydroxy-3-hydroxymethyloxindoles and 3-amino-3-hydroxymethyloxindoles with 79–96% yields. One-pot reductive hydroxymethylation, inexpensive rongalite (ca. $0.03/1 g)
Synthesis of blue emissive functionalized 9,9-disubstituted fluorene derivatives <i>via</i> BF<sub>3</sub>·OEt<sub>2</sub> mediated reaction of co-planar 9-(phenylethynyl)-9<i>H</i>-fluoren-9-ols with isatin imines
A Lewis acid mediated reaction of 9-(phenylethynyl)-9H-fluoren-9-ols with various isatin imines afforded a number of blue emissive 3-(2-oxo-2-phenyl-1-(9-(phenylamino)-9H-fluoren-9-yl)ethylidene)indolin-2-one and 3-(1-(9-hydroxy-9H-fluoren-9-yl)-2-oxo-2-phenylethylidene)indolin-2-one derivatives in excellent combined yield. A plausible mechanism for the formation of title compounds involving two pathways