A C(sp 2 )−H Dehydrogenation of Heteroarenes and Arenes by a Functionalized Aluminum Hydride

The 2‐aminophenylaluminum dihydride (2‐TMP‐C 6 H 4 )AlH 2  ( 2 ) has been prepared and characterized for the first time. Compound  2 features an intramolecular N⋅⋅⋅Al donor–acceptor bond. 2 reacted with N ‐methylpyrrole and N ‐methylindole (both at 50 °C) by means of the elusive AlH C(sp 2 )−H dehydroalumination to aluminum heteroaryls ( 3 and 4 ). Moreover, 2 reacted with PhCCSiMe 3 (at room temperature) and Ph 2 CCNR (R= i Pr or 2,6‐ i Pr 2 C 6 H 3 , at −30 to 20 °C ) to yield aluminaindene heterocycle ( 8 ) and alumina‐aza‐naphthalene heterocycle ( 9 and 10 ), respectively. These reactions underwent hydroalumination followed by AlH C(sp 2 )−H dehydroalumination. The reaction mechanism has been studied by combining experiment and quantum chemical calculations, with the result that the key heteroarene or arene C(sp 2 )−H bond activation is involved under cooperative interaction by the inherent N/Al donor/acceptor pair. The reported reactions open a straightforward route to heteroaryl and unique heterocyclic aluminum compounds.