95341-89-2Relevant academic research and scientific papers
Asymmetric Catalyses, 23. Optically Active Aminophosphanes - Synthesis and Use in the Rh-Catalyzed Enantioselective Hydrosilylation
Brunner, Henri,Weber, Hannelore
, p. 3380 - 3395 (2007/10/02)
New optically active P,N-ligands 6-15 were prepared by reaction of pyrrolimines, -amines, and pyridamines 1-5 with chlorophosphanes.With NEt3 as HCl scavenger the amine nitrogen NH groups were phosphinated selectively. n-BuLi as a base yielded a product mixture containing pyrrole nitrogen-phosphinated and doubly phosphinated compounds which could be separated by chromatography.On reaction with 2, the new P,N-ligands formed stable chelate complexes.In situ-catalysts from the optically active ligands 6-15 and 2 as well as the isolated Rh complexes 16-19 were used in the enantioselective hydrosilylation of acetophenone with diphenylsilane.Conversion and optical induction (up to 19.6percentee) in the formation of (+)- and (-)-phenylethanol depended on the Rh : ligand ratio, the Rh : substrate ratio, the reaction temperature, and the solvent.
Asymmetric Catalyses, 14. Enantioselective Hydrosilylation of Prochiral Ketones with Rh- and Pt-Complexes of Optically Active N-Chelate Ligands
Brunner, Henri,Reiter, Barbara,Riepl, Georg
, p. 1330 - 1354 (2007/10/02)
N-chelate ligands with a lateral chiral center, which derive from optically active primary amines, amino acids, and amino acid derivatives, catalyze in Rh and Pt complexes the enantioselective hydrosilylation of acetophenone, benzyl methyl ketone, and tert-butyl methyl ketone with diphenyl- and 1-naphthylphenylsilane.The ketones are transformed into the corresponding silyl ethers which on hydrolysis yield the alcohols 1-phenylethanol, 1-phenyl-2-propanol and 3,3-dimethyl-2-butanol. 37 N ligands 1 - 37 with 2 (I) and K (XX) as well as 21 isolated complexes II - XIX and XXI - XXIII are tested.The best optical inductions exceed considerably those which were obtained with optically active phosphane containing catalysts used up to now.
