82449-88-5Relevant academic research and scientific papers
ASYMMETRIC HYDROGENATIONS CATALYSED BY DIPHOSPHINITE RHODIUM COMPLEXES DERIVED FROM NATURAL TARTARIC ACID
Bourson, Jean,Oliveros, Laureano
, p. 77 - 84 (1982)
Two chiral diphosphinites, derived from natural tartaric acid, have been prepared and used as ligands for the preparation of two asymmetric hydrogenation catalysts, which were isolated in a crystalline state.After several weeks storage, these catalysts are still effective in the asymmetric hydrogenation of α-acetamido- and α-benzamido-cinnamic acid, citraconic acid, 2-phenyl-1-butene.In the hydrogenation of amino acid precursors the optical yields ranged from 14 to 44percent.Starting from a given substrate, each of the two enantiomers can be obtained by appropriate choice of one of our two catalysts, which are thus complementary to each other.The influence on the optical yield of various factors in the hydrogenations are considered.
SYNTHESE CHIRALER PHOSPHINOXIDE UND PHOSPHINE DURCH MICHAELIS-ARBUZOV-UMLAGERUNG
Brunner, H.,Zettlmeier, W.
, p. 247 - 257 (2007/10/02)
Several phosphinites and phosphites, derived from chiral alcohols, were synthesized.The phosphinites were subjected to a I2-catalyzed Michaelis-Arbuzov rearrangement.Phosphinites derived from primary alcohols give satisfactory yields of the corresponding phosphineoxides.Phosphinites synthesized from secondary alcohols also undergo the rearrangement but numerous byproducts appear in the reaction mixtures.Optical resolutions of chiral phosphineoxides by crystallization with optically active acids were not successful.The corresponding phosphines can easily be prepared by reduction of the oxides with trichlorosilane.
