Difluoromethylated aromatic compounds are of increasing importance in pharmaceuticals, agrochemicals and materials. Chlorodifluoromethane (ClCFH), an inexpensive, abundant and widely used industrial raw material, represents the ideal and most straightforward difluoromethylating reagent, but introduction of the difluoromethyl group (CFH) from ClCFH into aromatics has not been reported. Here, we describe a direct palladium-catalysed difluoromethylation method for coupling ClCFH with arylboronic acids and esters to generate difluoromethylated arenes with high efficiency. The reaction exhibits a remarkably broad substrate scope, including heteroarylboronic acids, and was used for difluoromethylation of a range of pharmaceuticals and biologically active compounds. Preliminary mechanistic studies revealed that a palladium difluorocarbene intermediate is involved in the reaction. Although numerous metal-difluorocarbene complexes have been prepared, the catalytic synthesis of difluoromethylated or difluoromethylenated compounds involving metal-difluorocarbene complexes has not received much attention. This new reaction therefore also opens the door to understand metal-difluorocarbene complex catalysed reactions.

Nickel-catalyzed carbodifunctionalization of alkenes is an efficient strategy for the construction of C–C bonds. However, applications of the strategy in dialkylation of alkenes remain underdeveloped due to the difficulties in suppressing competitive side reactions. We now describe a nickel-catalyzed tandem reaction by difluoroalkylation–alkylation of N-vinyl 2-pyrrolidinone with difluoroalkyl bromides and dialkylzinc reagents. The reaction can also extend to N-vinyloxazolidinone and N-vinylacetamide. This carbodifunctionalization reaction proceeds smoothly under mild reaction conditions with good functional group tolerance, providing a straightforward access to gem-difluoroalkylated 2-pyrrolidinone derivatives that are of interest in medicinal chemistry.

Although iron-catalyzed cross-coupling of Grignard reagents with alkyl halides has been well established, the adoption of the reaction for fluoroalkylations has not been reported because traditional catalytic systems often lead to defluorination reactions. Described herein is the investigation of an iron-catalyzed cross-coupling between arylmagnesium bromides and difluoroalkyl bromides with modified N,N,N',N'-tetramethyl-ethane-1,2-diamine (TMEDA) as a ligand. The use of this bulky diamine, in which a butylene is substituted at one carbon atom of the ethylene backbone in TMEDA, enables the iron-catalyzed difluoroalkylation under mild reaction conditions with a wide range of difluoroalkyl bromides, including vulnerable bromodifluoromethane, thus providing a general and cost-efficient route for applications in medicinal chemistry.