The synthesis of phosphine oxide-linked bis(oxazoline) ligands and their application in asymmetric allylic alkylation
作者:Yu Jin、Da-Ming Du
DOI:10.1016/j.tet.2012.02.078
日期:2012.5
The phosphine oxide-linked bis(oxazoline) ligands were designed and synthesized in two ways. One is the coupling of Grignard reagent derived from 2-(2-bromophenyl)oxazoline with phenylphosphonic dichloride, another route is the condensation of bis(2-formylphenyl)(phenyl)phosphine oxide with chiral amino alcohols followed by NBS oxidation. These new bis(oxazoline) ligands were applied in Pd-catalyzed
palladium-catalyzed allylicsubstitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wide substrate scope is shown by experimental and theoretical studies of its η3-allyl and η2-olefin complexes not to be a result of configurational interconversion of the biaryl unit, since the ligand
Practical Pd/C-Mediated Allylic Substitution in Water
作者:François-Xavier Felpin、Yannick Landais
DOI:10.1021/jo050952t
日期:2005.8.1
Pd/C-mediated allylic substitution in water is described as an interesting alternative to classical homogeneous conditions. The reaction applied to allylic acetates showed a wide range of compatibility with various nitrogen, sulfur, oxygen, and carbon nucleophiles. Notably, the method features inexpensive reagents and a nontoxic solvent. Moreover, measurement of the palladium content in water by ICP-MS
Palladium-catalyzedasymmetricallylic alkylation of 1,3-diphenyl-2-propenyl acetate (8a) with a dimethyl malonate–BSA–LiOAc system has been successfully carried out in the presence of novel chiral phosphine–oxazinane ligands such as 5b in good yields with good enantioselectivities (up to 95% ee).
Turning the Nitrogen Atoms of an Ar<sub>2</sub>
P−CH<sub>2</sub>
−N−N−CH<sub>2</sub>
−PAr<sub>2</sub>
Motif into Uniquely Configured Stereocenters: A Novel Diphosphane Design for Asymmetric Catalysis
作者:Eva Diehl née Knobloch、Reinhard Brückner
DOI:10.1002/chem.201706160
日期:2018.3.7
Hexahydropyridazines with CH2PAr2 groups at both N atoms are newly designed 1,4‐diphosphanes and were synthesized for the first time. Their N atoms assume a single configuration under the influence of stereocenters at C‐5 and C‐6. In the solid state, these N‐atoms bind the CH2PAr2 substituents axially. Combined with Pd0, N,N′‐chiral diphosphanes of this kind catalyzed Tsuji–Trost type allylations of dialkyl malonates
在两个N原子上均具有CH 2 PAr 2基团的六氢哒嗪是新设计的1,4-二膦烷,是首次合成。它们的N原子在C-5和C-6的立体中心的影响下呈单一构型。在固态下,这些N原子轴向结合CH 2 PAr 2取代基。与此类的Pd 0,N,N'-手性二膦烷结合,可有效地与乙酸外消旋1,3-二苯基烯丙基乙酸酯催化二甲基丙二酸酯的Tsuji-Trost型烯丙基化,且ee高达91% 。