Lithium can partner many of boron's neighbours in the periodic table, such as nitrogen in lithium amide, and carbon in methyllithium. But there have been no direct observations of the equivalent boryllithium compounds containing a negative boron atom. This type of boron anion shares the same number of valence electrons as its popular carbon cousin, the N-heterocyclic carbene. The Tokyo team demonstrated boryllithium's nucleophilic prowess in reactions with n-butyl chloride and benzaldehyde.
The work opens the door to new pathways in boron chemistry that will have a substantial impact on organic synthesis.