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The widespread use of phosphine ligand libraries is frequently hampered by the challenges associated with their modular preparation. Here, we report a protocol that appends arenes to arylphosphines to access a series of biaryl monophosphines via rhodium-catalyzed P(III)-directed ortho C–H activation, enabling unprecedented one-fold, two-fold, and three-fold direct arylation. Our experimental and theoretical findings reveal a mechanism involving oxidative addition of aryl bromides to the Rh catalyst, further ortho C–H metalation via a four-membered cyclometalated ring. Given the ready availability of substrates, our approach opens the door to developing more general methods for the construction of phosphine ligands. The widespread use of biaryl monophosphines is frequently hampered by the challenges associated with their modular preparation. Here, the authors report a protocol that appends arenes to arylphosphines to access a series of these compounds via rhodium-catalysed P(III)- directed ortho C–H activation, enabling one-fold, two-fold, and threefold direct arylation. [ABSTRACT FROM AUTHOR]

The use of an operationally convenient and stable silicon reagent (octamethyl‐1,4‐dioxacyclohexasilane, ODCS) for the selective silacyclization of (hetero)arenes via twofold C−H activation is reported. This method is compatible with N‐containing heteroarenes such as indoles and carbazoles of varying complexity. The ODCS reagent can also be utilized for silacyclization of other types of substrates, including tertiary phosphines and aryl halides. A series of mechanistic experiments and density functional theory (DFT) calculations were used to investigate the preferred pathway for this twofold C−H activation process. [ABSTRACT FROM AUTHOR]

Abstract: A straightforward method was developed for construction of aromatic compounds with a triphenylene core. The method involves Pd‐catalyzed annulative dimerization of o‐iodobiaryl compounds by double C−I and C−H bond cleavage steps. Simple reaction conditions are needed, requiring neither a ligand nor an oxidant, and the reaction tolerates a wide range of coupling partners without compromising efficiency or scalability. Significantly, the tetrachloro‐substituted synthon, 1,6,11‐trichloro‐4‐(4‐chlorophenyl)triphenylene, can be generated and used to prepare a series of fully fused, small graphene nanoribbons by a late‐stage arylation with arylboronic acids and a subsequent Scholl reaction. The synthetic strategy enables bottom‐up access to extended π‐systems in a controlled manner. [ABSTRACT FROM AUTHOR]