Thiocarbamate‐Directed
<i>ortho</i>
C−H Bond Alkylation with Diazo Compounds
作者:Shengnan Jin、Zhan Chen、Yingwei Zhao
DOI:10.1002/adsc.201900804
日期:2019.10.22
We herein report a rhodium catalysed insertion of C(sp2)−H bond into diazo derived carbenes directed by a thiocarbamate group. This reaction provides a direct and efficient pathway to the ortho alkylation of phenol derivatives with a broad substrate scope. The C−H activation process is accomplished through a reversible electrophilic rhodation.
We herein establish a multicomponent annulation method for the synthesis of valuable iminocoumarins using aryl thiocarbamates, internal alkynes, and sulfonamides as starting materials, which are safe and readily available. The key step is a Rh-catalyzed and sulfur-directed C—H bondactivation. Preliminary mechanistic investigations suggested that the nucleophilic attack of the sulfonamide on an active
Potassium Fluoride on Alumina: Synthesis of O-Aryl N,N-Dimethylthiocarbamates and their Rearrangement into S-Aryl N,N-Dimethyl-Thiocarbamates Under Microwave Irradiation
作者:Didier Villemin、Messaoud Hachemi、Mekki Lalaoui
DOI:10.1080/00397919608004558
日期:1996.7
A series of O-aryl N,N-dimethyl thiocarbamates have been prepared by the reaction of dimethylthiocarbamoyl chloride with phenols absorbed on potassium fluoride on alumina. The rearrangement of O-aryl N,N-dimethylthiocarbamate into S-aryl N,N-dimethyl thiocarbamate under microwave irradiation was also studied. The use of conductive support like graphite or silicon carbide allow these rearrangements although the O-aryl N,N-dimethylthiocarbamates have very low dielectric lost.