Tricarbonylchromium Complexes of 1,2-Dihydro-1,2-benzazaborines

1,2-Dihydro-2-phenyl-1,2-benzazaborine reacts with Cr(CO)3(CH3CN)3 in THF at 140 °C to form complex 18, in which the phenyl is η6-bound to chromium. 1,2-Dihydro-2-methyl-1,2-benzazaborine reacts with Cr(CO)3(CH3CN)3 in THF at 60 °C to form complex 23, in which the benzo ring is η6-bound to chromium. Treating 23 with potassium bis(trimethylsilyl)amide in THF forms the corresponding potassium salt 25, which on heating undergoes haptotropic isomerization to complex 26, in which the anionic heterocyclic ring is η6-bound to the chromium.