Quadruple Role of Pd Catalyst in Domino Reaction Involving Aryl to Alkyl 1,5‐Pd Migration to Access 1,9‐Bridged Triptycenes.

Iwata, Takayuki; Kumagai, Satoru; Yoshinaga, Tatsuro; Hanada, Masato; Shiota, Yoshihito; Yoshizawa, Kazunari; Shindo, Mitsuru

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.

TRIPTYCENES; SUZUKI reaction; ASYMMETRIC synthesis; PALLADIUM catalysts; CATALYSTS; ARYLATION; ACID catalysts

Chemistry - A European Journal, 2021, Vol 27, Issue 45, p11548

0947-6539

Academic Journal

10.1002/chem.202101728