Jason Williams

A procedure for the [Cp*Co^III]-catalyzed direct CH amidation of arenes with dioxazolone has been developed. This reaction proceeds under straightforward and mild conditions with a broad range of substrates, including anilides. A comparative study on the catalytic activity of Group 9 [{Cp*MCl₂}₂] complexes revealed the unique efficiency of the cobalt catalyst.

Pick of the bunch: A variety of arenes, including anilides, underwent direct CH amidation with dioxazolones in the presence of a cobalt catalyst with a Cp* ligand under mild and straightforward reaction conditions (see scheme; Piv=pivaloyl). A comparative study of Group 9 [Cp*M^III] complexes revealed the unique ability of the cobalt catalyst to promote this transformation efficiently.

A catalytic method for the nucleophilic fluorination of propargylic electrophiles is described. Our protocol involves the use of a Cu(NHC) complex as the catalyst and is suitable for the preparation of secondary and tertiary propargylic fluorides without the formation of isomeric fluoroallenes. Preliminary mechanistic investigations suggest that fluorination proceeds via copper acetylides and that cationic species are involved.

A carbene can: A Cu(NHC)-catalyzed nucleophilic fluorination of propargylic electrophiles was found to be suitable for the synthesis of secondary and tertiary propargylic fluorides without the formation of isomeric fluoroallenes (see scheme; NHC=N-heterocyclic carbene, Ms=methanesulfonyl, Ts=p-toluenesulfonyl). Preliminary mechanistic investigations suggest that fluorination proceeds via copper acetylides and involves cationic species.

Three-component couplings were achieved from common aryl halides, alkyl halides, and heteroarenes under palladium and norbornene co-catalysis. The reaction forges hindered aryl–heteroaryl bonds and introduces ortho-alkyl groups to aryl rings. Various heterocycles such as oxazoles, thiazoles and thiophenes underwent efficient coupling. The heteroarenes were deprotonated in situ by bases without the assistance of palladium catalysts.

Three-in-one: The heteroarylation of aryl iodides and ortho-alkylation of the aryl rings occur in a single operation. The palladium and norbornene cocatalyst system effectively promoted the cleavage of two CH bonds and the formation of two new CC bonds, including a very hindered aryl–heteroaryl bond.

Nickel nanoparticles, formed in situ and used in combination with micellar catalysis, catalyze Suzuki–Miyaura cross-couplings in water under very mild reaction conditions.

Under water: Nickel nanoparticles, formed in situ and used in combination with micellar catalysis, catalyze Suzuki–Miyaura cross-couplings in water under very mild reaction conditions. A wide range of substrates is tolerated and the reaction medium can be recycled.

The commonly used para-nitrobenzenesulfonyl (nosyl) protecting group is employed to direct the CH activation of amines for the first time. An enantioselective ortho-CH cross-coupling between nosyl-protected diarylmethylamines and arylboronic acid pinacol esters has been achieved utilizing chiral mono-N-protected amino acid (MPAA) ligands as a promoter.

Amine-directed: A new enantioselective ortho-CH cross-coupling reaction between nosyl-protected diarylmethylamines and arylboronic acid pinacol esters has been achieved with chiral mono-N-protected amino acids (MPAA) as chiral ligands. This reaction also demonstrates the feasibility of using a common protecting group to direct CH activation of amines for the first time.