Asymmetric Reactions Catalyzed by Chiral Metal Complexes. XLV. Efficient Preparation of Optically Active (S)-(-)-3-Methyl-.GAMMA.-butyrolactone by Catalytic Asymmetric Hydrogenation Using Chiral N-Substituted Pyrrolidinebisphosphine Rhodium Complexes.
Asymmetric Reactions Catalyzed by Chiral Metal Complexes. XLV. Efficient Preparation of Optically Active (S)-(-)-3-Methyl-.GAMMA.-butyrolactone by Catalytic Asymmetric Hydrogenation Using Chiral N-Substituted Pyrrolidinebisphosphine Rhodium Complexes.
Chiral Rhodium Complexes Derived From Electron-Rich Phosphine-Phosphites as Asymmetric Hydrogenation Catalysts
作者:Pablo Etayo、José L. Núñez-Rico、Anton Vidal-Ferran
DOI:10.1021/om200933b
日期:2011.12.26
Two new chiral cationic rhodium(I) complexes derived from electron-rich dicyclohexylphosphine-phosphite ligands were prepared from enantiopure Sharpless epoxy ethers. The best-performing catalyst system, which bears a less bulky methyl ether moiety, exhibited remarkably high enantioselectivity (up to 99% ee) and reactivity (up to >2500 TON) in asymmetric hydrogenation reactions of various functionalized
AXIALLY ASYMMETRIC PHOSPHORUS COMPOUND AND PRODUCTION METHOD THEREOF
申请人:TANAKA Ken
公开号:US20110218345A1
公开(公告)日:2011-09-08
[Problem to be Solved] To provide an axially asymmetric optically active biarylphosphorus compound that can easily produced without the step of optical resolution which was almost indispensable in conventional methods.
[Means for Solving the Problems] A method for producing an axially asymmetric phosphorus compound represented by the general formula (1), comprising a cycloaddition reaction of a compound having a triple bond with the use of a catalyst containing rhodium metal and an optically active bisphosphine.
(In the formula (1), R
1
and R
2
may be the same or different and independently are an alkyl group optionally having a substituent group, a cycloalkyl group optionally having a substituent group, an aryl group optionally having a substituent group, an alkoxy group optionally having a substituent group or an aryloxy group optionally having a substituent group; * is axial asymmetry.)
The Absolute Configuration of the C<sub>8</sub>-Atom in the Pyrrolizidine Moieties of the Senecio Alkaloids
作者:Roger Adams、D. Fleš
DOI:10.1021/ja01530a063
日期:1959.11
Asymmetric Reactions Catalyzed by Chiral Metal Complexes. XLV. Efficient Preparation of Optically Active (S)-(-)-3-Methyl-.GAMMA.-butyrolactone by Catalytic Asymmetric Hydrogenation Using Chiral N-Substituted Pyrrolidinebisphosphine Rhodium Complexes.
(S)-(-)-2-Methyl succinamic acid, which is a good precursor of (S)-(-)-3-methyl-γ-butyrolactone, can be prepared by homogeneous asymmetric hydrogenation of 2-methylene succinamic acid catalyzed by (2S, 4S)-N-substituted-4-(diphenylphosphino)-2-[(diphenylphosphino)-methyl]pyrrolidine-rhodium complexes. Various N-substituted pyrrolidine-bisphosphines were synthesized to find the optimum ligand for this purpose and to compare the effects of the N-substituents.