Anthranilamide-masked o-Iodoarylboronic Acids as Coupling Modules for Iterative Synthesis of ortho-Linked Oligoarenes

Abstract

Anthranilamide (AAM)-masked o-iodoarylboronic acids were prepared from AAM-masked arylboronic acids via Rucatalyzed o-CH silylation, followed by iododesilylation with ICl. The SuzukiMiyaura coupling of AAM-masked o-haloarylboronic acids with arylboronic acids proceeded under ligandfree conditions. Oligo(o-phenylene)s and oligo(naphthalene-2,3-diyl)s were synthesized via iterative SuzukiMiyaura coupling sequences.Interest in the synthesis and structure of ortho-linked oligoarenes and hetarenes has been increasing.14 They cannot adopt planar structure, but they form helical structures due to the steric repulsion of the substituents on the aromatic rings. In addition to their static helical structures, the dynamic change in the helical structures has attracted increasing attention from the viewpoint of application to functional materials.5 For instance, we have recently established solvent-dependent, reversible switch of helical conformation of poly(quinoxaline-2,3-diyl)s with high molecular weight. 6 This system was successfully applied to a new chiral catalyst system in which either enantiomer can be produced with high enantioselectivity from a single chiral catalyst.7 Although attractive, ortho-linked oligoarenes and hetarenes have not been explored in detail yet, mainly because of paucity of robust synthetic approaches. Therefore, it is highly desirable to establish general, efficient synthetic methods that would also allow the synthesis of functionalized oligoarenes in a sequence-selective manner.We have been interested in the development of crosscoupling-based organic synthesis, including iterative synthesis of oligoarene derivatives on the basis of boron-masking strategy using 1,8-diaminonaphthalene (DAN) as a highly effective masking group. 8 We subsequently established a removable ortho-directing group (o-DG), which is attached to the boron atom of the boronyl group and allows Ru-catalyzed o-silylation.

Poly(quinoxaline-2,3-diyl)s: A Fascinating Helical Macromolecular Scaffold for New Chiral Functions

“…In spite of the growing interests in o linked aromatic polymers, no much study has been made, mainly because of the dif culty in their synthesis. Poly(o phenylene)s, 5 poly(quinoline 2,3 diyl)s, 6 and poly(naphthalene 2,3 diyl)s 7 have been synthesized through cross coupling reaction and suggested to take helical structures. However, as far as using cross coupling chemistry, it is dif cult to obtain high polymers with controlled polymerization degrees.…”

An Efficient Ni/Pd Catalyzed Chemoselective Synthesis of 1,3,2‐Benzodiazaborininones from Boronic Acids and Anthranilamides

“…[7] These compounds with an anthranilamide (aam) substituent on the boron center [ArÀ B(aam)] are temporarily masked for their reactivity toward transmetalation, and have proven to be useful reagents in Suzuki-Miyaura cross-coupling reaction. [9] They have been applied to iridium-catalyzed stereoselective hydroboration of alkynes. [9] They have been applied to iridium-catalyzed stereoselective hydroboration of alkynes.…”

“…[8] The B(aam) moieties also serve as directing groups for catalytic ortho-C(aryl)À H silylation. [9] They have been applied to iridium-catalyzed stereoselective hydroboration of alkynes. [10] Conventional methods involve the construction of 1,3,2-benzodiazaborininones based on the condensation of boronic acid with commercially available anthranilamide in toluene under reflux.…”

A well-defined NHC–Ir(iii) catalyst for the silylation of aromatic C–H bonds: substrate survey and mechanistic insights

“…However, somewhat less attention has been paid to the development of well-defined organometallic complexes. 16c , 19 In this regard, the design of catalysts featuring N-heterocyclic carbenes (NHCs) as ancillary ligands has been surprisingly overlooked, 19 b especially when taking into account their success story in homogeneous catalysis. 20 …”