The dehydrogenative [4 + 2] annulation is a step- and atom-economical way to construct benzo-fused six-membered rings which are prevalent in natural products, pharmaceuticals and agrochemicals. Herein, we disclosed a visible-light induced dehydrogenative [4 + 2] annulation of benzothioamides and alkynes, which was performed undermild aerobic conditions and catalyzed by the metal-free heterogeneous
脱氢[4 + 2]环化是构建苯并稠合六元环的一种步骤和原子经济的方法,苯并稠合六元环在天然产物、药物和农用化学品中普遍存在。在此,我们公开了苯并硫酰胺和炔烃的可见光诱导脱氢[4 + 2]成环反应,该反应在温和有氧条件下进行,并由无金属异质光催化剂石墨氮化碳(gC 3 N 4)催化。多相光催化操作简单、条件温和,进展顺利,并以良好的收率产生了多种异硫色烯。gC 3 N 4在光化学反应中表现出优异的稳定性和可回收性。详细的机制研究表明,gC3 N 4在可见光照射下通过单电子转移过程促进了以硫为中心的自由基的形成。自由基中间体进一步介导与炔烃的[4+2]环化,产生异硫色烯。
De quelques dérivés nitrés et aminés de la benzanilide, de la thiobenzanilide et du 2-phényl-benzothiazole et des colorants azoïques qui en dérivent
作者:H. Rivier、Jean Zeltner
DOI:10.1002/hlca.193702001102
日期:——
Acylperoxycoumarins as<i>ortho</i>-CH Acylating Agent<i>via</i>a Palladium(II)-Catalyzed Redox-Neutral Process
作者:Prakash Ranjan Mohanta、Arghya Banerjee、Sourav Kumar Santra、Ahalya Behera、Bhisma K. Patel
DOI:10.1002/adsc.201600258
日期:2016.6.30
palladium(II)‐catalyzed biomimetic aliphatic acyl (‐COR) group transfer was observed from acyl‐α‐peroxycoumarins to the orthoCH sites of directingarenes. Here, the CH activation is associated with a concomitant acyl group transfer via a Pd(II)‐catalyzed, redox‐neutral process. While methods for ortho aroylation (‐COAr) are well documented ortho acylation (‐COR) processes are scarce, hence the present
Competing oxygen migrations inortho nitro aromatic thioamides on electron impact
作者:D. V. Ramana、S. K. Viswanadham
DOI:10.1002/oms.1210180407
日期:1983.4
AbstractInteresting competitive oxygen migrations from the nitro group to the nitrogen and to the sulfur have been noticed during the mass spectral decomposition of ortho nitro aromatic thioamides on electron impact. The migration of the oxygen to the nitrogen of the thioamide function results in the formation of stable o‐nitrosothiobenzoyl cation. The other novel ortho effect noticed in the ortho isomers is the transfer of an oxygen from the nitro group to the sulfur followed by the ejection of SO from the molecular ions. A mechanism involving the initial oxygen migration to the sulfur through a favourable 6‐membered transition state followed by cyclization with the concomitant expulsion of SO is proposed for this process. Other interesting decomposition processes occurring as a consequence of this ortho effect have also been noticed. The proposed mechanisms for these processes are supported by mass analysed ion kinetic energy spectra and high voltage scans.