2,2′‐Diborabiphenyl: A Lewis Acid Analogue of 2,2′‐Bipyridine

A chelating Lewis acid analogue of the ubiquitous “bipy” ligand system has been prepared from the dichlorodiborane 1 (see scheme). Treatment of 1 with a variety of Lewis bases, such as the bifunctional benzo[c]cinnoline shown, leads to loss of two equivalents of Me3SiCl and formation of the Lewis base adducts of 2,2′‐diborabiphenyl. Some of these compounds are isoelectronic with polycyclic aromatic hydrocarbons and exhibit interesting optical and redox properties.