A Pd‐catalyzed domino reaction of 1,8,13‐tribromo‐9‐methoxytriptycenes is reported. Under conventional Suzuki coupling conditions, the triptycenes underwent multiple transformations to give 1,9‐bridged triptycenes. Based on mechanistic investigations, a single Pd catalyst functions as Pd0, PdII and PdIV species to catalyze four distinct processes: (1) aryl to alkyl 1,5‐Pd migration, (2) intramolecular arylation, (3) homocoupling of phenylboronic acid and (4) Suzuki coupling. DFT calculations revealed that 1,5‐Pd migration likely proceeds via both concerted PdII and stepwise PdIV routes. Asymmetric synthesis of the chiral triptycenes, as well as optical resolution, and further transformation are also reported.

Herein, we describe Hiyama coupling via intramolecular substituent transfer from silicon on one blade of triptycenes to another to yield 1,8,13-trisubstituted chiral triptycenes. This reaction is attributed to the proximity effect of substituents on triptycene, which plays an important role in not only the formation of the oxy-palladacycle but also the activation of the silyl group to facilitate σ-bond metathesis. After bromination and nucleophilic ring opening, the second intramolecular Hiyama coupling provided various 1,8,13trisubstituted chiral triptycenes. The optical resolution of 1,8,13-triptycene afforded an optically active form for the first time.

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A Pd‐catalyzed domino reaction of 1,8,13‐tribromo‐9‐methoxytriptycenes is reported. Under conventional Suzuki coupling conditions, the triptycenes underwent multiple transformations to give 1,9‐bridged triptycenes. Based on mechanistic investigations, a single Pd catalyst functions as Pd0, PdII and PdIV species to catalyze four distinct processes: 1) aryl‐to‐alkyl 1,5‐Pd migration, 2) intramolecular arylation, 3) homocoupling of phenylboronic acid and 4) Suzuki coupling. More information can be found in the Communication by T. Iwata, M. Shindo et al. (DOI: 10.1002/chem.202101728).

The proximity of Si−O−Pd plays an important role not only in the formation of the oxy‐palladium species in intramolecular Hiyama coupling, but also in the activation of the silyl group to facilitate intramolecular substituent transfer. Various 1,8,13‐trisubstituted chiral triptycenes were synthesized by using this reaction. More information can be found in the Research Article by T. Iwata, M. Shindo, and co‐workers (DOI: 10.1002/chem.202300988).