Monomeric organoaluminium complexes RAl(OR*)(2) and R2AlOR* with an optically active amino alkoxide ligand

The reactions of trialkylaluminium, R3Al, with (S)-(-)alpha,alpha-diphenyl- 2-pyrrolidinyl-methanol have been investigated, in which unusual bis-comple xes RA1(OR*)(2) were obtained [OR* = (S)-alpha,alpha-diphenyl-2-pyrrolidiny l-methoxide (Dpm), R = Me (1), Et (2), 1-Nor (3)]. A similar reaction carri ed out with R = t-Bu yields, by contrast, the expected mono-alkoxide R2AlOR * (4). All compounds were characterised by X-ray crystallography and NMR sp ectroscopy. The molecular structures are monomeric. In 1-3, the aluminium c entres bonded to the nitrogen atoms of two chelating ligands are five-coord inate, while the metal atom contained in 4 is tetrahedrally surrounded. The absolute structures of all complexes were determined from X-ray diffractio n data. The formation of the dative Al-N bonds is stereospecific in all cas es. (C) 2000 Elsevier Science S.A. All rights reserved.