An aerobic visible-light driven photoredox catalytic formation of 2-substitutedbenzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C–H functionalization and C–S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the
Use of Molecular Oxygen as a Reoxidant in the Synthesis of 2-Substituted Benzothiazoles via Palladium-Catalyzed CH Functionalization/Intramolecular CS Bond Formation
作者:Kiyofumi Inamoto、Chisa Hasegawa、Junpei Kawasaki、Kou Hiroya、Takayuki Doi
DOI:10.1002/adsc.201000604
日期:2010.10.4
Molecularoxygen (O2) was successfully employed as a reoxidant in cyclizations of thiobenzanilides 1a–s through a palladium-catalyzed CH functionalization/intramolecular CS bondformation process, leading to an efficient, green method for the synthesis of 2-arylbenzothiazoles 2a–s. Addition of cesium fluoride (CsF) greatly enhanced the reactions, which produced variously substituted 2-arylbenzothiazoles
Palladium-Catalyzed C-H Cyclization in Water: A Milder Route to 2-Arylbenzothiazoles
作者:Kiyofumi Inamoto、Yoshinori Kondo、Kanako Nozawa
DOI:10.1055/s-0031-1291164
日期:2012.7
medium in palladium-catalyzed C–H cyclization of thiobenzanilides. Reactions efficiently proceeded under considerably mild conditions such as 40 °C in water, providing a more practical, greener method for the synthesis of 2-arylbenzothiazoles. For somesubstrates, the addition of an amphiphilic surfactant greatly enhanced the process. The method represents a rare example of palladium-catalyzed C–H functionalization
在钯催化的硫代苯甲酰苯胺的 C-H 环化中,水被成功用作反应介质。反应在相当温和的条件下有效进行,例如在 40 °C 的水中,为合成 2-芳基苯并噻唑提供了一种更实用、更环保的方法。对于某些基材,添加两亲性表面活性剂大大增强了该过程。该方法代表了在水中进行钯催化的 C-H 功能化过程的一个罕见例子。
Facile Conversion of Thioamides into the Corresponding Amides in the Presence of Tetrabutylammonium Bromide
Desulfurization of thioamides was accomplished using a semicatalytic amount of Bu4NBr. The corresponding amides were obtained in high yields, with good functional group compatibility.
硫胺的脱硫采用了半催化量的Bu4NBr,得到相应的酰胺,产率高,功能团兼容性好。
Riboflavin as Photoredox Catalyst in the Cyclization of Thiobenzanilides: Synthesis of 2-Substituted Benzothiazoles
作者:Lydia M. Bouchet、Adrián A. Heredia、Juan E. Argüello、Luciana C. Schmidt
DOI:10.1021/acs.orglett.9b04384
日期:2020.1.17
Benzothiazoles are synthesized from thiobenzanilides using riboflavin as a photosensitizer and potassium peroxydisulfate as a sacrificial oxidizing agent under visible light irradiation. The methodology accepts a broad range of functional groups and affords the 2-substitutedbenzothiazoles by transition-metal-free organic photoredoxcatalysis under very mild conditions.