99135-92-9Relevant academic research and scientific papers
Optically active 3,4-bis-(diphenylphosphino)-pyrrolidine, and rhodium complexes, containing it as chiral ligands
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, (2008/06/13)
There are described new optically active 3,4-bis-(diphenylphosphino)-pyrrolidines of the formula STR1 wherein Ph is a phenyl group and R is hydrogen, an alkyl group, an arylalkyl group or an acyl group, rhodium complexes containing a compound of formula (I) as its chiral ligands, said rhodium complexes having the formula where (en)2 is two molecules of a monoolefin or one molecule of a diolefin, A is an optically active compound of formula (I) and X- is a tetrafluoroborate, hexafluorophosphate or a perchlorate ion, and use of the rhodium complexes as catalysts for the homogeneous asymmetric hydrogenation of unsubstituted or β-substituted α-acylamino-acrylic acids.
Enantioselective Catalysis, 4. Synthesis of N-Substituted (R,R)-3,4-Bis(diphenylphosphino)pyrrolidines. The Use of their Rhodium Complexes for the Asymmetric Hydrogenation of α-(Acylamino)acrylic Acid Derivatives
Nagel, Ulrich,Kinzel, Elke,Andrade, Juan,Prescher, Guenter
, p. 3326 - 3343 (2007/10/02)
A simple synthesis of (R,R)-3,4-bis(diphenylphosphino)pyrrolidine (6a) and some N-substituted derivatives 6b-m is described. 6l and 6m are optically active tetraphosphanes, composed of two (R,R)-3,4-bis(diphenylphosphino)pyrrolidine units and a dicarboxylic residue.The structure of the parent compound 6a was determined by X-ray diffraction.From the phosphanes 6a-m the cationic 1,5-cyclooctadiene-bisphosphane-rhodium complexes 7a-m were prepared.The complexes 7l and 7m are ligand bridged bis(rhodium) dications.The complexes 7a-m were used for the asymmetric catalytic hydrogenation of the α-(acylamino)acrylic acid derivatives 9a-l.Enantiomeric excesses up to 100percent were achieved.Between 1 and 70 at the optical yields do not depend on the hydrogen pressure.The substrate/catalyst ratio can be as high as 50000/1.
