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Creators/Authors contains: "Yeung, Kap‐Sun"

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  1. Abstract A simple and efficient nitrile‐directedmeta‐C−H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U‐shaped template to achieve a molecular U‐turn and assemble the large‐sized cyclophane transition state for the remote C−H activation, a synthetically useful phenyl nitrile functional group could also direct remotemeta‐C−H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remotemeta‐selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand‐containing Pd–Ag heterodimeric transition state (TS) favors the desired remotemeta‐selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non‐directedmeta‐C−H activation. Substituted 2‐pyridone ligands were found to be key in assisting the cleavage of themeta‐C−H bond in the concerted metalation–deprotonation (CMD) process. 
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