73473-97-9Relevant academic research and scientific papers
Synthesis and characterization of chiral mono N-heterocyclic carbene-substituted rhodium complexes and their catalytic properties in hydrosilylation reactions
Steinbeck, Martin,Frey, Guido D.,Schoeller, Wolfgang W.,Herrmann, Wolfgang A.
supporting information; experimental part, p. 3945 - 3954 (2011/12/22)
Different chiral mono-substituted N-heterocyclic carbene complexes of rhodium were prepared, starting from [Rh(COD)Cl]2 (COD = cyclooctadiene) by addition of free N-heterocyclic carbenes (NHC), or an in-situ deprotonation of the corresponding iminium salt. All new complexes were characterized by spectroscopy methods. In addition, the structures of chloro(η4-1,5-cyclooctadiene)(1,3-di-[(1R,2R,3R,5S)-2,6, 6-trimethylbicyclo[3.1.1]hept-3-yl] imidazolin-2-ylidene)rhodium(I) (5a), chloro(η4-1,5-cyclooctadiene)(1,3-di-[(1R,2S,5R) -2-isopropyl-5-menthylcyclohex-1-yl]imidazol-2-ylidene)rhodium(I) (5b) and chloro(η4-1,5-cyclooctadiene)(1,3-di-[(2R,4S,5S) -2-methyl-4-phenyl-1,3-dioxacyclohex-5-yl]imidazolin-2-ylidene)rhodium(I) (5i) were analyzed by DFT-calculations. The enantioselective hydrosilylation of acetophenone, ethylpyruvate and n-propylpyruvate with diphenylsilane and hydrolysis was carried out with chiral C2-symmetrical mono-substituted N-heterocyclic carbene rhodium complexes giving for the first time an enantioselective excess of up to 74% ee in the case of the n-propylpyruvate.
Asymmetric Syntheses, V. Optically Active 5-Amino-4-phenyl-1,3-dioxanes and Their Influence on the Stereoselectivity of the Asymmetric Strecker-Synthesis
Weinges, Klaus,Klotz, Klaus-Peter,Droste, Holger
, p. 710 - 721 (2007/10/02)
From (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol (1) and aldehydes or ketones 2a-e, respectively, the appropriate 5-amino-4-phenyl-1,3-dioxanes 3a-e are prepared.With benzaldehyde they form well crystallizing azomethines 4a-e.The conformation and configu
