Streamlined Synthesis of Polycyclic Conjugated Hydrocarbons Containing Cyclobutadienoids via C-H Activated Annulation
Zexin Jin1, Yew Chin Teo1, Nicolo G Zulaybar1
1Department of Chemistry, Stanford University , Stanford, California 94305, United States.
Abstract:
The juxtaposition of fused cyclobutadienoid (CBD) with benzenoid creates intriguing alternating antiaromatic and aromatic conjugation. Synthetic accessibility of such molecules, however, has been challenging and limited in scope. We report a modular and streamlined synthetic strategy to access a large variety of polycyclic conjugated hydrocarbons with fused CBD. Synthesis was achieved through efficient palladium-catalyzed C-H activated annulation between abundant aryl bromides and oxanorbornenes, followed by aromatization under acidic conditions. The influence of four-membered ring was examined using spectroscopy, crystallography, and computation. This strategy will facilitate exploration on the chemical, structural, and electronic properties of such conjugated systems containing CBD.
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