Enantioselective synthesis of β-amino acids based on BINAP—ruthenium(II) catalyzed hydrogenation
摘要:
BINAP-Ru(II) catalyzed hydrogenation of beta-substituted (E)-beta-(acylamino)acrylic acids allows efficient enantioselective synthesis of beta-amino acids. The Z double bond isomers which possess an intramolecular hydrogen bond between amide and ester groups are more reactive but are hydrogenated with poor enantioselectivity. BINAP-Rh(I) complexes afford only moderate stereoselectivity with the opposite sense of enantioselection.
2, 3-Bis(dialkylphosphino)pyrazine derivative, process of producing the same, and metal complex having the same as ligand
申请人:Imamoto Tsuneo
公开号:US20070021610A1
公开(公告)日:2007-01-25
An optically active 2,3-bis(dialkylphosphino)pyrazine derivative represented by formula (1) is disclosed. The pyrazine derivative is preferably a quinoxaline derivative represented by formula (2). In formula (1) and (2), R
1
is preferably a t-butyl or adamantyl group, and R
2
is preferably a methyl group.
wherein R
1
is a substituted or unsubstituted, straight chain or branched alkyl group having 2 to 10 carbon atoms; R
2
is a substituted or unsubstituted, straight chain or branched alkyl group having fewer carbon atoms than R
1
; and R
3
and R
4
, which may be the same or different, are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, or R
3
and R
4
are taken together to form a saturated or unsaturated ring.
wherein R
1
and R
2
are as defined above; and R
5
is a monovalent substituent.
An Air-Stable P-Chiral Phosphine Ligand for Highly Enantioselective Transition-Metal-Catalyzed Reactions
作者:Tsuneo Imamoto、Keitaro Sugita、Kazuhiro Yoshida
DOI:10.1021/ja053458f
日期:2005.8.1
A new P-chiralphosphineligand, (R,R)-2,3-bis(tert-butylmethylphosphino)quinoxaline, has been prepared by the reaction of enantiomerically pure tert-butylmethylphosphine-borane with 2,3-dichloroquinoxaline. This ligand, in contrast to most of the previously reported P-chiralligands, is an air-stable solid and exhibits excellent enantioselectivities in both Rh-catalyzed asymmetric hydrogenations and
Cycloolefin phosphine ligands and their use in catalysis
申请人:Degussa AG
公开号:EP1595888A1
公开(公告)日:2005-11-16
The present invention concerns novel bidentante optionally N-containing P-ligands of general formula (I)
embracing a two-ring-system and processes for synthesizing them, transition metal complexes of these compounds and their use as catalysts.
Chiral diphosphine ligands based on camphor: synthesis and applications in asymmetric hydrogenations
作者:Renat Kadyrov、Ilyas Z. Ilaldinov、Juan Almena、Axel Monsees、Thomas H. Riermeier
DOI:10.1016/j.tetlet.2005.08.103
日期:2005.10
The synthesis of a novel class of atropisomer chiral diphosphineligands with a bornene framework is described. The new ligands showed in Rh catalyzed asymmetric hydrogenation of α- and β-enamides very high ee’s (more than 99%).
Idiopathic pulmonaryfibrosis (IPF) is a chronic progressive lung disease with a typical survival time between three to five years. Two drugs, pirfenidone and nintedanib have been approved for the treatment of IPF, but they have limited efficacy. Thus, the development of new drugs to treat IPF is an urgent medical need. In this paper we report the discovery of a series of orally active pyrimidin-4(3H)-one