Direct Arylation of Polycyclic Aromatic Hydrocarbons through Palladium Catalysis

Abstract

We have discovered that the combination of Pd(OAc)(2)/o-chloranil can catalyze the direct C-H bond arylation of polycyclic aromatic hydrocarbons (PAHs) with arylboroxins that occurs selectively at the K-region. The sequential integration of Pd-catalyzed direct arylation of PAHs and FeCl(3)-mediated cyclodehydrogenation is effective in rapidly extending a parent PAH π-system with high directionality.

Synthesis of extended polycyclic aromatic hydrocarbons by oxidative tandem spirocyclization and 1,2-aryl migration

“…A variety of synthetic methodologies for constructing various π-extended PAHs have been developed towards achieving high efficiency and novelty56789101112131415. Among them, since the seminal advance has been made by Müllen and Spiess et al .…”

“…Inspired by this observation, we anticipated that if a radical cation forms selectively at the alkene moiety of BPMF by employing appropriate single-electron oxidation systems, the subsequent spirocyclization and 1,2-aryl migration tandem process may take place to give the desired twisted molecule dibenzo[ g , p ]chrysene (DBC), which is an intriguing holding block of discotic molecules, fluorescent and charge carrier-transporting materials. Diverse synthetic methods of the DBC derivatives have been reported, such as oxidation of electron-rich bis(biaryl)acetylenes, oxidation of electron-rich tetraarylethylenes, intramolecular aromatic C–H/C–Br coupling, double Suzuki-Miyaura coupling, and Pd-catalysed coupling of C–H bonds of small PAHs with dimethyldibenzosilole13141519202122232425262728. On the basis of our reaction design, we herein describe a novel dehydrogenative PAH synthetic methodology based on the oxidative spirocyclization and 1,2-aryl migration tandem process.…”

Biaryl Synthesis through Metal‐Catalyzed C–H Arylation

“…They also applied this coupling reaction to the synthesis of the core structure of SCH-785532, which is known as a BACE inhibitor. In the same year, Itami [184] reported a direct arylation of a PAH with arylboronic acids to generate a π-expanded PAH. Treatment of pyrene 142 with arylboroxine 143 in the presence of Pd(OAc) 2 and o-chloranil as an oxidant, followed by cyclization under stoichiometric FeCl 3 , produced PAH 144.…”

“…The filtrate was concentrated and the residue was subjected to preparative thin layer chromatography (hexane/EtOAc = 10 : 1) to afford 2-(naphthalen-2-yl)benzoxazole (93.2 mg, 95%) as a white solid. 1 [184]. The reaction mixture was filtrated over silica gel (eluent: CH 2 Cl 2 , 100 ml) and the volatiles were removed under reduced pressure.…”

Strategies in Organic Synthesis for Condensed Arenes, Coronene, and Graphene

“…Itami and coworkers established that pyrene can be selectively coupled with an arylboronic acid in an intermolecular fashion in the presence of a Pd-catalyst and stoichiometric amounts of chloranil as an oxidant [73]. With suitable coupling partners small graphene-type structures are accessible, which can be planarized using cyclodehydrogenation conditions (Scheme 28).…”