Homogeneous catalysis

Selectively generating “skipped” dienes, where two carbon–carbon double bonds are separated by a saturated carbon center, is an interesting problem in organic chemistry, with few reliable, catalytic methods currently available. Here, the authors report branched selective hydroallylation of terminal alkynes with allylic bromides to form skipped dienes, via cobalt catalysis.

The selective functionalization of trifluoromethyl groups is challenging due to the inertness of the C–F bonds. Here the authors report a method for the carbodefluorination of C–F bonds of fluoroalkyl ketones via a carbene-initiated rearrangement strategy.

The direct addition of isocyanides to cyclopropenes is challenging. Here, the authors report a catalytic cyclopropene-isocyanide [5 + 1] benzannulation catalyzed by an (N-heterocyclic carbene)Ni(II) complex; this method enables the preparation of fused and multi-substituted anilines and unsymmetrically functionalized spiro-ring structures.

Biaryls are privileged structural motif used in the discovery and design of therapeutics with high affinity and specificity for a broad range of protein targets. Herein, the authors develop a robust strategy for para-C–H arylation of arenes with a range of (het)aryl iodides, including bioactive molecules.

Nitrene transfer chemistry is an effective strategy for introducing C–N bonds, but inexpensive reaction systems for tunable, intermolecular chemoselective nitrene transfer for late-stage amination of unsaturated natural products remains a challenge. Here, the authors report copper catalysed chemoselective allylic C–H amination and catalyst-free visible-light induced aziridination of alkenes through nitrene transfer.

Aryldifluoromethyl aryl ethers (ArCF₂OAr’) are powerful structural motifs to improve druggability, however, their targeted synthesis remains challenging. Here, the authors report the efficient synthesis of ArCF₂OAr’ motifs via nickel-catalyzed aryloxydifluoromethylation with arylboronic acids, and their application in the total synthesis of a difluoromethylated PD-1/PD-L1 immune checkpoint inhibitor with enhanced antitumor efficacy over the non-fluoro congener.