Reductive linear- and cyclo-trimerization of isocyanides using an Al–Al-bonded compound

Dialumane 1 reacts with tBuNC to produce a reductive dimerization adduct [LAl(tBuN[double bond, length as m-dash]C-C[double bond, length as m-dash]NtBu)AlL] (2). In the presence of Na, 1 can promote linear- and cyclo-trimerization of isocyanides, affording products [Na][LAl{(tBuNC)3}AlL] (3 and 4) and [Na][LAl{(tBuNC)3}Al(C[triple bond, length as m-dash]N)L] (5), the latter of which features a unique aromatic tri(tert-butylimino)deltate dianion [C3N3(tBu)3]2-.