Single, double, triple bonds and chains: the formation of electron-precise B-B bonds.

The construction of boron-boron bonds, despite the intense synthetic interest in diboranes and the high B-B bond enthalpy, is still difficult, uncontrollable, and unpredictable. Methods for the construction of B-B multiple bonds are rarer still. These problems have witnessed some progress in recent years; this Minireview attempts to provide a background to the history of B-B bond synthesis and summarize the recent results in the area.