122977-49-5Relevant academic research and scientific papers
Asymmetric hydrogenation of itaconic acid and enol acetate derivatives with the Rh-TangPhos catalyst
Tang, Wenjun,Liu, Duan,Zhang, Xumu
, p. 205 - 207 (2007/10/03)
(Matrix presented) The Rh-TangPhos catalyst has been used for asymmetric hydrogenation of itaconic acid and enol acetate derivatives. A variety of chiral 2-substituted succinic acids and chiral acetates have been obtained in excellent ee values (up to 99% ee).
Synthesis of efficient chiral bisphosphine ligands, modified DIOPs, (4R,5R)-4-(Diaryl- or dialkylphosphino)methyl-5-(diarylphosphino)methyl-2,2- dimethyl-1,3-dioxolanes, and their use in rhodium(I)-catalyzed asymmetric hydrogenations
Morimoto,Chiba,Achiwa
, p. 1149 - 1156 (2007/10/02)
Modified DIOPs, (4R,5R)-4-(diaryl- or dialkyphosphino)methyl-5- (diarylphosphino)methyl-2,2-dimethyl-1,3-dioxolanes, were prepared on the basis of our design concept, and used as ligands for the rhodium(I)-catalyzed asymmetric hydrogenations of ketopantolactone, itaconic acid, dimethyl itaconate, and β-aryl-substituted itaconic acid derivatives. A neutral rhodium(I)-complex of (4R-trans)-dicyclohexyl[[5- [(diphenylphosphino)methyl]-2,2-dimethyl-1,3-dioxolan-4-yl]methyl]phosphine (DIOCP) bearing both a dicyclohexylphosphino group and a diphenylphosphino group was found to be a more efficient catalyst than the original DIOP in the asymmetric hydrogenation of ketopantolactone. Modified DIOPs bearing electron-donating groups at their para positions were efficient ligands for the rhodium(I)-catalyzed assymetric hydrogenations of itaconic acid and its derivatives; in particular, (4R-trans)-[(2,2-dimethyl-1,3-dioxolane-4,5- diyl)bis(methylene)]bis[bis(4'-methoxy-3',5'-dimethylphenyl)phosphine] (MOD- DIOP) bearing both a p-methoxy group and two m,m'-methyl groups on each phenyl group showed much higher enantioselectivity and catalytic activity than DIOP.
HIGHLY EFFICIENT ASYMMETRIC HYDROGENATION OF ITACONIC ACID DERIVATIVES CATALYZED BY A MODIFIED DIOP-RHODIUM COMPLEX
Morimoto, Toshiaki,Chiba, Mitsuo,Achiwa, Kazuo
, p. 735 - 738 (2007/10/02)
A modified DIOP analogue bearing 4-methoxy and 3,5-dimethyl groups on each phenyl group has been synthesized.The rhodium complex of the ligand has been found to give very high optical yields in the asymmetric hydrogenation of itaconic acid and its derivatives bearing β-aryl groups, the products of which are key-intermediates for optically active lignan derivatives.
