Unusual Reactions of NacNacAl with Urea and Phosphine Oxides

The reaction of cyclic urea 1,3-dimethyl-2-imidazolidinone with the aluminum­(I) compound NacNacAl (<b>1</b>) gives an unexpected adduct of urea with the isomerized aluminum­(III) hydride NacNac′AlH­(OSIMe) (<b>3</b>). A related reaction of <b>1</b> with phosphine oxides results in cleavage of the PO bond and formation of hydroxyl derivatives NacNac′Al­(OH)­(OPR₃) [R = Ph (<b>5</b>) and Et (<b>6</b>)]. Density functional theory calculations revealed that these reactions proceed via a bimolecular mechanism in which either the basic aluminum­(I) center or the transient AlO species deprotonate the methyl group of the NacNac ligand