Thiocarbamate-Directed Tandem Olefination–Intramolecular Sulfuration of Two <i>Ortho</i> C–H Bonds: Application to Synthesis of a COX-2 Inhibitor
作者:Wendong Li、Yingwei Zhao、Shaoyu Mai、Qiuling Song
DOI:10.1021/acs.orglett.8b00089
日期:2018.2.16
A palladium-catalyzed dual ortho C–H bond activation of aryl thiocarbamates is developed. This tandem reaction initiates by thiocarbamate-directed ortho C–H palladation, which leads to favorable olefin insertion rather than reductive elimination. The oxidative Heck reaction followed by another C–H activation and sulfuration affords the dual-functionalized products. This reaction provides a concise
series of O-aryl (alkyl) N,N-dimethylthiocarbamates were synthesized in good yields (70–77%) by reacting substituted phenols or alkyl alcohol with inexpensive, stable, and environmentally benign tetramethylthiuram disulfide (TMTD) in the presence of NaH. By avoiding use of the toxic and corrosive N,N-dialkylthiocarbamoyl chloride, the method provides a green and facile preparation for some important precursors
Studies of the Thiocarbonyl Compounds. III. The Mechanism of the Thermal Rearrangement of Aryl Thionocarboxylates
作者:Aritsune Kaji、Yoshiaki Araki、Koshin Miyazaki
DOI:10.1246/bcsj.44.1393
日期:1971.5
The thermal rearrangement of aryl thionocarboxylates was kinetically investigated in diphenyl ether. The rate constants of the rearrangement of aryl N,N-dimethylthionocarbamates were well correlated with the σ− values, but the plots of the electron-releasing para-substituents deviated slightly on the lower side of the meta correlation line. A good linear free-energy relationship existed between the