Synthesis of β‑Difluoroalkylated Acrylonitriles in the Presence of Copper Powder

A highly regio- and stereoselective copper-mediated cyanodifluoro­alkylation of alkynes with ethyl difluoroiodoacetate and trimethylsilyl cyanide (TMSCN) is described. The three-component coupling reaction provides straightforward access to a variety of useful difluoroalkyl-substituted acrylonitriles. The introduction of the nitrile unit is of great importance in drug discovery for the modification of this fragment. Preliminary mechanistic investigations indicate that a vinyl iodide intermediate and a difluoroalkyl radical might be involved in this transformation

Palladium-Catalyzed Intermolecular Aryldifluoroalkylation of Alkynes

A palladium-catalyzed aryldifluoroalkylation of alkynes with ethyl difluoroiodoacetate and arylboronic acids as reaction partners is described. The alkyne difunctionalization process provides various aryldifluoroalkylated products in one pot under mild reaction conditions. A wide range of alkynes and diverse arylboronic acids are compatible with these reaction conditions. High reaction efficiency and broad substrate scope are the notable features of this transformation. Preliminary mechanistic investigations indicate that a difluoroalkyl radical addition pathway is involved in this transformation

Ruthenium-Catalyzed Direct C–H Amidation of Arenes: A Mechanistic Study

We report mechanistic studies of C–H activitation/amidation reactions using azides as the amino source catalyzed by [RuCl₂(<i>p</i>-cymene)]₂. We have achieved two intermediates in the catalytic cycle (C₅H₄NC₆H₄)­Ru­(<i>p</i>-cymene)Cl and (C₅H₄NC₆H₄)­NArRu­(<i>p</i>-cymene)Cl (Ar = NO₂C₆H₄SO₂). Furthermore, the process from (C₅H₄NC₆H₄)­Ru­(<i>p</i>-cymene)Cl to (C₅H₄NC₆H₄)­NArRu­(<i>p</i>-cymene)Cl was monitored by ¹⁹F NMR and a ruthenium–imido species was proposed to explain the formation of the azacyclopropane analogue

Copper-Catalyzed Intermolecular Cyanotrifluoromethylation of Alkenes

A novel and highly practical reaction for the copper-catalyzed intermolecular cyanotrifluoromethylation of alkenes is presented here. This methodology provides a general and straightforward way to synthesize a variety of useful CF₃-containing nitriles, which can be used for further preparation of pharmaceutically and agrochemically important compounds in synthetic organic chemistry

Copper-Catalyzed Three-Component Cyano­trifluoro­methyla­tion/Azido­trifluoro­methyla­tion and Carbo­cycli­zation of 1,6-Enynes

A novel three-component strategy for the cyano­trifluoro­methyla­tion/azido­trifluoro­methyla­tion and carbocyclization of 1,6-enynes is developed. The reaction proceeds smoothly under a moderate temperature by using a copper catalyst, which provides a rapid and concise access to addition–carbocyclization products. Furthermore, the products obtained can be useful building blocks in discoveries of lead compounds and other biologically active CF₃-containing heterocycles

Copper-Catalyzed Intermolecular Cyanotrifluoromethylation of Alkenes

A novel and highly practical reaction for the copper-catalyzed intermolecular cyanotrifluoromethylation of alkenes is presented here. This methodology provides a general and straightforward way to synthesize a variety of useful CF₃-containing nitriles, which can be used for further preparation of pharmaceutically and agrochemically important compounds in synthetic organic chemistry

Silver-Promoted Oxidative Cyclization of 1,6-Enynes: Highly Regioselective Synthesis of Phosphorated Fluorene Derivatives

A silver-promoted oxidative cyclization of 1,6-enynes with disubstituted phosphine oxides is developed for the synthesis of fluorene derivatives. The reaction proceeds with high regioselectivity by constructing one C–P bond and two C–C bonds in one step. Moreover, reduction of the pentavalent phosphine enlarges the application scope of the product

Silver-Promoted Oxidative Cyclization of 1,6-Enynes: Highly Regioselective Synthesis of Phosphorated Fluorene Derivatives

A silver-promoted oxidative cyclization of 1,6-enynes with disubstituted phosphine oxides is developed for the synthesis of fluorene derivatives. The reaction proceeds with high regioselectivity by constructing one C–P bond and two C–C bonds in one step. Moreover, reduction of the pentavalent phosphine enlarges the application scope of the product

Lewis Acid Catalyzed [4 + 3] Cycloaddition of Propargylic Alcohols with Azides

An unprecedented Lewis acid catalyzed [4 + 3] cycloaddition reaction is described that provides a straightforward route to polycyclic products containing an imine-based indole azepine scaffold, starting from readily available internal tertiary alkynols and azides. This cycloaddition protocol provides efficient and atom-economical access to a new class of fascinating imine-containing products in satisfactory yields, which has shown good application in the construction of seven-membered <i>N</i>-heterocycles

Lewis Acid Catalyzed [4 + 3] Cycloaddition of Propargylic Alcohols with Azides

An unprecedented Lewis acid catalyzed [4 + 3] cycloaddition reaction is described that provides a straightforward route to polycyclic products containing an imine-based indole azepine scaffold, starting from readily available internal tertiary alkynols and azides. This cycloaddition protocol provides efficient and atom-economical access to a new class of fascinating imine-containing products in satisfactory yields, which has shown good application in the construction of seven-membered <i>N</i>-heterocycles