Synthesis and characterization of chiral organogallium and organoaluminum alcoholates with intramolecular nitrogen stabilization. X-ray structural analysis of dimethylgallium-(S)-2-dimethylamino-3-methyl-1-butanolate, dimethylgallium-(S)-2-dimethylam

摘要

The reactions of trimethylgallium and trimethylaluminium with optically active alcohols yield [Me2GaOCH2CHRNMe2](2) [R = Me (S) 6, Pr-i (S) 7, Bu-i (S) 8, Bz (S) 9, Et (R:S > 90:10) 10] and [Me2AlOCH2CHRNMe2](2) [R = Bu-i (S) 11. Et (R:S > 90:10) 12]. respectively. The compounds have been characterized by H-1-,C-13-NMR and mass spectroscopy. They undergo a dynamic process with respect to the dissociation and association of the Ga-N or Al-N dative bond resulting in equilibria between four-and five-coordinate metal atoms. The structures of 7, 9 and 10 were determined by single crystal X-ray diffraction. The molecules exist as dimers containing a M2O2 four-membered ring. 6-11 exclusively consist of dimers with enantiomerically equal ligands: 12, on the contrary contains diastereomeric dimers featuring different NMR spectra. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 48]