Reversible 1,1-hydroaluminations and C–H activation in reactions of a cyclic (alkyl)(amino) carbene with alane

Abstract

Varying the reaction ratio of cyclic (alkyl)(amino) carbene (cAAC^Et) with AlH₃·NEtMe₂ leads to the isolation of (cAAC^EtH)AlH₂·NEtMe₂1 and (cAAC^EtH)₂Al(μ-H)₂AlH₂·NEtMe₂2 and the first example of a monomeric dialkyl-aluminum hydride (cAAC^EtH)₂AlH 3. VT and ¹H–¹H EXSY NMR experiments of 3 demonstrated the isomerization of the diastereomers of 3via the first instance of reversible hydride migration between the Al and the C center. In addition, heating solutions of 3 at 100 °C affords (cAAC^EtH)Al(CHC(Et)₂CH₂C(Me)₂NC₆H₃(iPr)C(Me)CH₂) 4 with loss of H₂.