DBU-Promoted Formal [4+2] Annulation Reactions of o-Chloromethyl Anilines with Azlactones
作者:Jianfeng Xu、Haojie Ji、Chonglong He、Hongjie Gao、Weijun Fu
DOI:10.1055/s-0040-1706549
日期:2021.4
An efficient 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated formal [4+2] annulation reaction of aza-ortho-quinone methides (aza-oQMs) (generated from o-chloromethyl anilines) with enolates (formed from azlactones) is disclosed, delivering biologically significant 3,4-dihydroquinolin-2(1H)-one derivatives in moderate to good yields. The salient features of this reaction include readily accessible
Synthesis of Benzo[<i>e</i>][1,4]thiazepines by Base-Induced Formal [4+3] Annulation Reaction of Aza-<i>o</i>-quinone Methides and Pyridinium 1,4-Zwitterionic Thiolates
作者:Lijie Zhang、Ling Fang、Hao Huang、Chaofan Wang、Fang Gao、Zhiyong Wang
DOI:10.1021/acs.joc.1c02433
日期:2021.12.17
The base-induced formal [4+3] annulation reaction of in situ-formed aza-o-quinone methides and pyridinium1,4-zwitterionicthiolates is reported. This protocol provides a novel and reliable method for the synthesis of biologically interesting benzo[e][1,4]thiazepine derivatives in synthetically useful yields. In addition, postsynthetic modification results in the formation of its sulfoxide and sulfone
报道了原位形成的氮杂-邻-醌甲基化物和吡啶鎓1,4-两性离子硫醇盐的碱诱导形式[4+3]环化反应。该协议提供了一种新颖且可靠的方法,用于以合成有用的产量合成具有生物学意义的苯并[ e ][1,4]硫氮杂衍生物。此外,合成后修饰导致其亚砜和砜衍生物的形成。
Enantioselective Annulations for Dihydroquinolones by in Situ Generation of Azolium Enolates
作者:Anna Lee、Ashkaan Younai、Christopher K. Price、Javier Izquierdo、Rama K. Mishra、Karl A. Scheidt
DOI:10.1021/ja505880r
日期:2014.7.30
A convergent, catalytic asymmetric formal [4 + 2] annulation for the synthesis of dihydroquinolones has been developed. Carboxylic acids can be employed as precursors to NHC enolates through an in situ activation strategy. Simultaneous generation of a reactive aza-o-quinone methide under the basic conditions employed for NHC generation leads to a dual activation approach.
Lewis Base and Brønsted Base Dual-Catalyzed Formal [4+3] Cycloaddition Reaction: Synthesis of Aza-Spirocycloheptane Oxindole
An intermolecular, quaternary carbon center forming [4+3] cycloaddition reaction catalyzed by Lewis base and Bronsted base has been successfully developed. The dual catalysis exhibits a superior ability to enable a previously challenging reaction, and the corresponding quaternary aza-spirocycloheptane oxindole scaffolds are efficiently synthesized with moderate to high yields.