A facile and efficient synthesis of substituted pyridine-2,6(1H,3H)-diones via an intramolecular [5 + 1] annulation of readily available α-alkenoyl-α-carbamoyl ketene-S,S-acetals mediated by phosphorus bromide (PBr3) under very mild conditions is described.
One-Pot Synthesis of Substituted Isothiazol-3(2<i>H</i>)-ones: Intramolecular Annulation of α-Carbamoyl Ketene-<i>S</i>,<i>S</i>-acetals via PIFA-Mediated N-S Bond Formation
作者:Dewen Dong、Jie Huang、Yumei Lu、Baofu Qiu、Yongjiu Liang、Nan Li
DOI:10.1055/s-2007-983875
日期:2007.9
A facile and efficient syntheticroute towards; highly substituted isothiazol-3(2H)-ones 2 from readily available U.-carbamoyl ketene-S,S-acetals 1 is presented. The key step features the formation of an N-acylnitrenium ion, generated from the oxidization of substituted amides with the hypervalent iodine reagent phenyliodine(III) bis(trifluoroacetate) (PIFA), and its succeeding intramolecular amidation
Tandem [3+1+1+1] Heterocyclization of α‐Acyl Ketene Dithioacetals with Ammonia and Methanol: Rapid Assembly of Polysubstituted Pyrimidines
作者:Youkun Wang、Linlin Yan、Xiaoxuan Zhang、Fengrui Xiang、Xiaojun Li、Shengnan Li、Xiaoning Song
DOI:10.1002/ejoc.202200237
日期:2022.4.21
An expeditious [3+1+1+1] heterocyclization of α-acyl ketene dithioacetals and renewable methanol as well as economical NH4OAc is established to construct densely functionalized pyrimidine derivatives. The domino conversion proceeds effectively through sequential keto imination/C−S aminolysis/cyclocondensation/dehydroaromatization processes under O2 atmosphere by harnessing the dual activities of CuCl2
[3+2] Cycloaddition of Propargylamines and α-Acylketene Dithioacetals: A Synthetic Strategy for Highly Substituted Pyrroles
作者:Yu-Long Zhao、Chong-Hui Di、Si-Di Liu、Jia Meng、Qun Liu
DOI:10.1002/adsc.201200375
日期:2012.12.14
A new [3+2] cycloaddition strategy for the direct synthesis of highlysubstituted pyrroles from the readily available α-acylketene dithioacetals (or related substrates) and commercially available propargylamines under mild metal-free conditions has been developed. In this reaction, the acyl group plays a critical role in driving the conjugate addition of propargylamine and further cyclization to give
Domino Reaction of α-Acetyl-α-carbamoyl Ketene Dithioacetals with Vilsmeier Reagents: A Novel and Efficient Synthesis of 4-Halogenated 2(1<i>H</i>)-Pyridinones
A novel and efficient route to 4-halogenated N-substituted 2(1H)-pyridinones has been developed via a one-pot domino process of readily available α-acetyl-α-carbamoyl ketene dithioacetals with Vilsmeier reagents. These 4-halogenated-2(1H)-pyridinones constitute useful intermediates due to the easy elaboration on either the pyridinone core (by the displacement of the halogen atom) or functionality transformation