Synthesis and molecular structure of an abnormal carbene–gallium chloride complex

Abstract

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 2 with GaCl₃ gives a 4-functionalized N-heterocyclic carbene : GaCl₃ adduct (6), reaction of 4 with GaCl₃ affords the first abnormal carbene–gallium chloride complexes (5).