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
A Phosphorus(III)‐Mediated (4+1)‐Cycloaddition of 1,2‐Dicarbonyls and Aza‐
<i>o</i>
‐Quinone Methides to Access 2,3‐Dihydroindoles
作者:Kaitlyn E. Eckert、Antonio J. Lepore、Brandon L. Ashfeld
DOI:10.1002/hlca.201900192
日期:2019.12
A (4+1)‐cycloaddition is reported between 1,2‐dicarbonyls and aza‐o‐quinonemethide precursors to access2,3‐dihydroindoles bearing a tetra‐substituted carbon center. The utilization of dioxyphospholenes as carbene surrogates provided dihydroindoles in 20–90 % yield, wherein the electronic nature of the dioxyphospholene impacts its role in the reaction.
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。
Synthesis of Functionalized 4,1‐Benzothiazepines via a [4+3] Annulation between Aza‐
<i>o‐</i>
Quinone Methides and Pyridinium 1,4‐Zwitterionic Thiolates
The [4+3] annulation of aza-o-quinone methides and pyridinium1,4-zwitterionicthiolates has been developed for the one-step synthesis of functionalized 2,3-unsaturated 4,1-benzothiazepines under mild and metal-free conditions. The produced 4,1-benzothiazepines can easily be converted into biologically interesting sulfoxides and sulfones via selective oxidization with m-CPBA.