Rapid Access to Nanographenes and Fused Heteroaromatics by Palladium‐Catalyzed Annulative π‐Extension Reaction of Unfunctionalized Aromatics with Diiodobiaryls

Abstract

Efficient and rapid access to nanographenes and pextended fused heteroaromatics is important in materials science.H erein, we report ap alladium-catalyzed efficient one-step annulative p-extension (APEX) reaction of polycyclic aromatic hydrocarbons (PAHs) and heteroaromatics, producing various p-extended aromatics.I nt he presence of ac ationic Pd complex, triflic acid, silver pivalate,a nd diiodobiaryls,d iverse unfunctionalized PAHs and heteroaromatics were directly transformed into larger PAHs,n anographenes,a nd p-extended fused heteroaromatics in as ingle step.I nt he reactions that afford[ 5]helicene substructures, simultaneous dehydrogenative ring closures occur at the fjord regions to form unprecedented larger nanographenes.T his successive APEX reaction is notable as it stiches five aryl-aryl bonds by CÀHf unctionalization in as ingle operation. Moreover,t he unique molecular structures,c rystal-packing structures,photophysical properties,and frontier molecular orbitals of the thus-formed nanographenes were elucidated. p-Extended fused aromatics have recently received much

Diversity-oriented synthesis of nanographenes enabled by dearomative annulative π-extension

“…For example, phenanthrene (1h), 1-phenylphenanthrene (1i), [4]helicene (1j), and chrysene (1k), which all feature both K-and M-regions, could be selectively transformed to the desired M-APEX products (5ha-5ka) as single constitutional isomers. In addition, previously reported πextending agents for K-APEX 16,17…”

“…To this end, we have established several palladium-catalyzed APEX reactions that occur at the K-region (convex armchair edge) of PAHs (Fig. 1b, K-APEX), realizing the synthesis of various nanographenes 16,17 . Clar, Scott, and others have achieved Diels-Alder-type APEX reactions at the bay-region (concave armchair edge) of PAHs (Fig.…”

Palladium‐Catalyzed Direct Diarylation of 2‐Benzyl‐1,2,3‐triazole: a Simple Access to 4‐Aryl‐ or 4,5‐Diaryl‐2‐benzyl‐1,2,3‐triazoles and Phenanthro[9,10‐d][1,2,3]triazoles

“…and 2‐benzyl‐1,2,3‐triazole (1 equiv.) was also attempted [12b] . However, using the reaction conditions of Scheme 6, with 3 equiv.…”

Twofold π-Extension of Polyarenes via Double and Triple Radical Alkyne peri-Annulations: Radical Cascades Converging on the Same Aromatic Core

“…On the other hand, bottom-up protocols which build NGs and GNRs from small PAH building blocks build size and complexity in a controlled fashion. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] The synthetic toolset available for the bottom-up preparation and modification of PAHs, NGs, and GNRs expands continuously to fine-tune their electronic properties and improve their solubility and processability. The high energy content and carbon-richness of alkynes makes them a privileged functional group within this reaction toolset.…”