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

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Hideto Ito, Recent Publication
Rapid Access to Nanographenes and Fused Heteroaromatics by Palladium-Catalyzed Annulative π-Extension Reaction of Unfunctionalized Aromatics with Diiodobiaryls

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

2017.8.17
Hideto Ito, Recent Publication

Wataru Matsuoka, Hideto Ito,* Kenichiro Itami*
Angew. Chem. Int. Ed. 2017, 56, 12224. DOI: 10.1002/anie.201707486
Highlighted in Organometallic Chemistry: Current Trends in Organometallic and Synthetic Chemistry

[Expansion of aromatic ring]

Efficient and rapid access to nanographenes and π-extended fused heteroaromatics is important in materials science. Here we report a Pd-catalyzed efficient one-step annulative π–extension (APEX) reaction of PAHs and heteroaromatics, producing various π-extended aromatics. In the presence of a cationic Pd complex, triflic acid, silver pivalate, and diiodobiaryls, diverse unfunctionalized PAHs and heteroaromatics were directly transformed into larger PAHs, nanographenes, and π-extended fused heteroaromatics in a single step. In the reactions affording [5]helicene substructures, simultaneous dehydrogenative ring closures occur at the fjord regions to form unprecedented larger nanographenes. This successive APEX reaction is notable as it stiches five aryl-aryl bonds by C-H functionalization in a single operation. Moreover, the unique molecular structures, crystal-packing structures, photophysical properties, and frontier molecular orbitals of the thus-formed nanographenes were elucidated

See our latest review on APEX reaction：Angew. Chem. Int. Ed. 2017, 56, early view

Comments by authors:

Mr. Wataru Matsuoka (PhD course student, left)
今回のAPEX反応は僕にとって非常に思い入れのある反応です。同じような分子変換反応は既に当研究室で開発されていましたが、APEX反応の実用性の向上や今後の応用展開を視野に入れ、より一般性の高い反応条件の探索に取り組みました。文字通り、0からの反応開発であり、ガスクロマトグラフィーで初めて目的物のピークが見えたときは嬉しさのあまり一人で震えました。また、偶然の発見ではありますが、APEX反応とScholl反応が同時に起こる反応条件の発見も印象深いです（上図）。低収率に留まっていることは残念ですが、簡単に大きなπ共役系を構築でき、「カッコイイ反応」を開発出来たと思います(笑)。本論文は、第一著者として初めての論文であり、論文作成の大変さなど、多くの事を学べました。今後も本研究で得た知識や技術を元に、よりカッコイイAPEX反応を開発したいと思います。

Dr. Hideto Ito (right)
After first publisment of our 1st generation APEX reaction（Nature Commun. 2015), two years have already passed. Two years ago, Wataru had started the reasearch on the development of 2nd generation APEX reaction and did over 2000 experiments but he have obtained not good results day after day. However he never give up and continue to explore many many conditions, reagents and catalysts, and he finally found great reaction as the 2nd APEX reaction. Congratulations, Wataru!!