Flow microreactors have allowed an efficient extended Pummerer reaction of ketene dithioacetal monoxides with anilines by precise control of unstable sulfonium intermediates and spatial separation ...
The first demonstration of the hydrogenation of sulfoxidesunder atmospheric H2 pressure is reported. The highly efficient reaction is facilitated by a heterogeneous Ru nanoparticle catalyst. The mild reaction conditions enable the selective hydrogenation of a wide range of functionalized sulfoxides to the corresponding sulfides. The high redox ability of RuOx nanoparticles plays a key role in the
Two-Step, Practical, and Diversity-Oriented Synthesis of Multisubstituted Benzofurans from Phenols through Pummerer Annulation Followed by Cross-coupling
作者:Kei Murakami、Hideki Yorimitsu、Atsuhiro Osuka
DOI:10.1246/bcsj.20140241
日期:2014.12.15
Practical and diversity-oriented synthesis of multisubstituted benzofurans has been accomplished from simple phenols through a Pummerer annulation/cross-coupling sequence. Operationally simple and rapid reactions of phenols with ketene dithioacetal monoxides (KDMs) with the aid of trifluoroacetic anhydride provide the corresponding 2-methylsulfanylbenzo[b]furans. The scope of the reaction encompasses phenols and KDMs having a broad range of substituents. The remaining methylsulfanyl group in the annulation products is converted to various aryl groups through cross-coupling reactions that we improved specially to this end. This two-step approach to multisubstituted benzofurans is powerful enough to synthesize highly fluorescent benzofuran derivatives as well as the naturally occurring Eupomatenoid family.
synthesis of fluorinated benzofurans from polyfluorophenols has been accomplished by means of a sigmatropic dearomatization/defluorination strategy composed of three processes: (1) interrupted Pummerer reaction of ketene dithioacetal monoxides with polyfluorophenols followed by [3,3] sigmatropicrearrangement, (2) Zn‐mediated smooth reductive removal of fluoride from the dearomatized intermediate, and
Treatment of 2-methylene-1,3-dithiane 1-oxide with aryl iodides under palladium catalysis in the presence of potassium carbonate and tetrabutylammonium bromide leads to the Mizoroki–Heck arylation to yield 2-(arylmethylene)-1,3-dithiane 1-oxides in high yields.