A highly efficient and regioselectivedirectC–H trifluoromethylation of pyridine based on an N-methylpyridine quaternary ammonium activation strategy has been developed. A variety of trifluoromethylpyridines can be obtained in good yield and excellent regioselectivity by treating the pyridinium iodide salts with trifluoroacetic acid in the presence of silver carbonate in N,N-dimethylformamide. The
The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity.
Synthesis and fungicidal activity of nitrophenylpyridines
作者:Majed Hassan、A. T. Soldatenkov、E. I. Andreeva、P. K. Radzhan、V. O. Fedorov、N. S. Prostakov
DOI:10.1007/bf00819968
日期:1993.5
Data are given in this communication on the preparation of new substituted nitrophenylpyridines and their fungicidalactivity and on the activity of some diand trialkylsubstituted nitrophenylpyridines synthesized by us previously [5]. This is a continuation of studies [2-4] on the synthesis and fungicidal properties of pyridine derivatives. The following new compounds were obtained by the nitration
Ru(II)‐Catalyzed Hydroarylation of in situ Generated 3,3,3‐Trifluoro‐1‐propyne by C−H Bond Activation: A Facile and Practical Access to β‐Trifluoromethylstyrenes
in situ generated 3,3,3-trifluoropropyne from the inexpensive 2-bromo-3,3,3-trifluoropropene was developed to access β-trifluoromethylstyrenes. A wide range of (hetero)arenes was functionalized leading selectively to the E-isomers. Detailed mechanistic studies and DFT calculations supported the involvement of an arene-free cyclometallated Ru(II) species and a bis-cyclometallated Ru complex as key intermediate