113452-18-9Relevant academic research and scientific papers
Enantioselective Catalysis, VIII. - New 1,2-Bisphosphane Ligands with Four Stereogenic Centers and Additional Methoxy Groups for Asymmetric Catalytic Hydrogenation
Nagel, Ulrich,Bublewitz, Alexander
, p. 1061 - 1072 (2007/10/02)
The synthesis of N-acyl derivatives of all possible diastereomers of -3,4-bispyrrolidine and -3,4-bispyrrolidine in optical pure form is described.Palladium and rhodium complexes with these ligands were prepared.The enantioselective hydrogenation of acetamidocinnamic acid with these rhodium complexes was studied at H2 pressures between 1 and 75 bar.There is only a small influence of the 2-methoxy group in the ligand on the catalytic hydrogenation when compared with the respective unsubstituted diastereomer.Te structure of pyrrolidine-P,P'>diiodopalladium was determined by X-ray diffraction.Key Words: 3,4-Bis(phosphanyl)pyrrolidines / Palladium complexes / Rhodium complexes / Asymmetric hydrogenation
Enantioselective Catalysis, 5. - New Ligands with Four Stereogenic Centers. Synthesis and Separation of the Three Diastereomeric -3,4-Bis(methylphenylphosphino)-pyrrolidines
Nagel, Ulrich,Rieger, Bernhard
, p. 1123 - 1132 (2007/10/02)
From (3R,4R)-3,4-bis(diphenylphosphino)pyrrolidine (1a) or the N-benzyl derivative 1b -3,4-bis(phenylphosphino)pyrrolidine (2a-*) resp. its N-benzyl derivative 2b-* were prepared as diastereomeric mixture.From 2a-* isomerically pure (PR,3R,4R,P'S)-3,4-bis(benzylphenylphosphino)pyrrolidine (3a-3) was prepared. -3,4-bis(methylphenylphosphino)pyrrolidine (4a-*), obtained from 2a-*, was a mixture of the three possible diastereomers.This mixture could be separated through the palladium complexes of the N-tert-butoxycarbonyl derivatives 8c-*. diiodopalladium(II) (8c-1) and for comparison (1,5-cyclooctadiene)rhodium-(I) tetrafluoroborate (11) were characterised by X-ray crystallography.
