Reactions Of Al-N Based Active Lewis Pairs With Ketones And 1,2-Diketones: Insertion Into Al-N Bonds, C-C And C-N Bond Formation And A Tricyclic Saturated Tetraaza Compound

The monomeric aluminum hydrazideiBu(2)Al-N(C10H15)(NC5H10) (1) features a strained AlN(2)ring and is an efficient active Lewis pair. It reacted with 2,3-diphenyl-2-cyclopropen-1-one by insertion of the C=O group into an Al-N bond, cleavage of the C(3)ring and formation of an AlOC(3)heterocycle (2). Diacetyl, Me(O)C-C(O)Me, and1afforded by insertion of keto groups into both Al-N bonds a heterocyclic alpha-keto-hemihydrazinal coordinated to aluminum (3).3contains fused AlO(2)C(2)and C(2)N(2)heterocycles. In an unexpected reaction, benzil, PhC(O)-C(O)Ph, afforded by C-C and C-N bond formation a unique tricyclic dimer (4) of the hydrazone H10C5N-N=C10H14, which is the starting material for the synthesis of1. This reaction may involve a radical process, and benzil radical anions coordinated to Al were detected as by-products. In contrast,1reacted with simple ketones to yield alcoholates [iBu(2)AlOR](2)[R = OC(H)(Ph)-C equivalent to C-Ph (5), OCHPh2(6)] by retrohydroalumination and reaction of resultingiBu(2)Al-H with C=O groups.