Synthesis of Biphenylenes and Their Higher Homologues by Cyclization of Aryne Derivatives

This investigation demonstrates that a series of biphenylenes can be easily prepared from their corresponding halobiphenyls by the cyclization of in situ generated 2′,3′‐didehydro‐2‐lithiobiphenyls at low temperature. Two remarkable advantages of this synthetic method include 1) the lack of any need for transition‐metal catalysts or reagents in the cyclization, and 2) the ability to obtain C1‐functionalized products by treating the reaction intermediate 1‐lithiobiphenylene with an electrophilic reagent. π‐Extended derivatives, such as benzobiphenylenes, dibenzobiphenylene, linear/angular [3]phenylenes, and biphenyleno[2,3‐b]biphenylenes, were synthesized similarly using suitable biaryls or teraryls. Biphenylene können durch die Organolithium‐vermittelte Cyclisierung von Halogenbiphenylen über ein Arin‐Intermediat leicht und effizient bei niedriger Temperatur erhalten werden. Diese Methode bietet Vorteile für die direkte und gezielte Funktionalisierung an der C1‐Position.