A novel cyclization reaction of pyridinium 1,4-zwitterionic thiolates and propiolic acidderivatives mediated by triethylamine is described, which allows the facile synthesis of indolizines under mild reaction conditions. The net transformation involves an acetylide-driven formal [5 + 1] annulation reaction followed by a spontaneous ring-contraction/sulfur extrusion process of transient pyridothiazine
practical protocol for the synthesis of fully substituted pyrazoles from pyridinium 1,4-zwitterionic thiolates and hydrazonoyl chlorides in excellent yields under mild conditions is described. The transformation proceeds via an unusual [[3 + 3] - 1] pathway, which involves a formal [3 + 3] cascade cyclization followed by a spontaneous ring-contraction/sulfur extrusion reactionfrom 4H-1,3,4-thiadiazine intermediates
Pyridinium 1,4-zwitterionic thiolates as a useful class of sulfur-containing synthons: application to the synthesis of 2,5-dihydro-1,4,5-thiadiazepines
A novel [4+3] cascade cyclization reaction of pyridinium 1,4-zwitterionic thiolates with azoalkenes derived from α-halo hydrazones in situ has been developed. This reaction was found to allow expedient access to an array of 2,5-dihydro-1,4,5-thiadiazepines. Libraries of highly functionalized sulfoxide and sulfone analogues of 2,5-dihydro-1,4,5-thiadiazepines were also obtained via selective oxidation
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.