RESUMO
A copper-catalyzed fluoroalkylation-cyclization sequence of alkenes and alkynes enables the synthesis of fluorinated tetra- and dihydroimidazopyridines in moderate to excellent yields within 1 h at 70 °C. This reaction, which is carried out using copper(I) acetate as the catalyst, makes use of a new class of functionalized tetrafluoroethyl reagents based on a hypervalent iodine scaffold.
RESUMO
This chapter describes synthesis, structural properties, activation modes, and applications of hypervalent iodine reagents for trifluoromethylation, thereby focusing on recent advances.
RESUMO
The direct electrophilic trifluoromethylation of silyl ketene imines (SKIs) with hypervalent iodine reagents leads to the formation of quaternary α-trifluoromethyl nitriles in good yields. This new reaction has been carried out with a variety of substituted SKIs under solvent-free conditions using a vanadium(IV) catalyst (5â mol %). The corresponding products may be transformed into useful organofluorine building blocks.
RESUMO
Chiral-anion phase-transfer catalysis (PTC) has been applied towards the enantioselective fluorocyclization reactions of 1,3-dienes. The method affords unprecedented fluorinated benz[f]isoquinoline and octahydroisoquinoline products in high yields and up to 96 % ee. New fluorinated amine reagents outperformed Selectfluor in the desired transformation.
RESUMO
Effective CF(3) transfer: Various electron-rich nitrogen heterocycles (pyrazoles, triazoles, and tetrazoles) can be directly N-trifluoromethylated by a hypervalent iodine reagent in an efficient manner. The optimized procedure, which includes an in situ silylation of the substrate followed by an acid-catalyzed CF(3) transfer, provides ready access to a series of new and previously challenging or inaccessible NCF(3) compounds.
