Synthesis and molecular structure of an abnormal carbene-gallium chloride complex.

Low temperature reaction of N-heterocyclic carbene : BEt3 with nBuLi (in THF) initially gives the C4-lithiated N-heterocyclic carbene : BEt3 complex (4), which isomerizes to the C2-lithiated abnormal N-heterocyclic carbene : BEt3 complex (2) in refluxing THF. While reaction of with GaCl3 gives a 4-functionalized N-heterocyclic carbene : GaCl3 adduct (6), reaction of with GaCl3 affords the first abnormal carbene-gallium chloride complexes (5).