Novel diphosphines, their complexes with transisition metals and their use in asymmetric synthesis
申请人:——
公开号:US20040260101A1
公开(公告)日:2004-12-23
The invention relates to novel diphosphines, in optically pure or racemic form, of formula (I):
1
in which:
R
1
and R
2
are a (C
5
-C
7
)cycloalkyl group, an optionally substituted phenyl group or a 5-membered heteroaryl group; and
A is (CH
2
—CH
2
) or CF
2
.
The invention further relates to the use of a compound of formula (I) as a ligand for the preparation of a metal complex useful as a chiral catalyst in asymmetric catalysis, and to the chiral metal catalysts comprising at least one ligand of formula (I).
Catalytic Enantioselective Arylation of Glyoxylate with Arylsilanes: Practical Synthesis of Optically Active Mandelic Acid Derivatives
作者:Kohsuke Aikawa、Yūta Hioki、Koichi Mikami
DOI:10.1002/asia.201000522
日期:2010.11.2
a little does the trick! The catalytic enantioselective arylation using chiral dicationic palladium complexes provides a reliable and useful access to enantiomerically enriched mandelic‐acid derivatives. Significantly low catalyst loading (down to 0.002 mol %) as well as easy catalyst handling are the advantage of this practical method.
Synthesis and Molecular Modeling Studies of SYNPHOS, a New, Efficient Diphosphane Ligand For Ruthenium-Catalyzed Asymmetric Hydrogenation
作者:Sébastien Duprat de Paule、Séverine Jeulin、Virginie Ratovelomanana-Vidal、Jean-Pierre Genêt、Nicolas Champion、Philippe Dellis
DOI:10.1002/ejoc.200200634
日期:2003.5
A new, optically active, atropisomeric diphosphane ligand, (2,3,2′,3′-tetrahydro-5,5′-bi(1,4-benzodioxin)-6,6′-diyl)bis-(diphenylphosphane) (SYNPHOS®), has been synthesized, characterized, and used in ruthenium-catalyzed asymmetric hydrogenations. This new ligand has been compared with other atropisomeric diphosphanes (BINAP and MeO-BIPHEP) with respect to their dihedral angles calculated by molecular
Enantioselective Friedel-Crafts Alkylation of Thiophenes with Ethyl Glyoxylate: Easy Access to Chiral Secondary Alcohols
作者:Zhong Huang、Jingchang Zhang、Yuqiang Zhou、Nai-Xing Wang
DOI:10.1002/ejoc.201001455
日期:2011.2
Friedel–Craftsalkylation reactions of ethylglyoxylate with various thiophenes to give the corresponding chiralsecondaryalcohols were demonstrated. The majority of these reactions proceeded with good enantioselectivities (up to 91 %) and satisfactory isolated yields. Notably, we found that 2-substituted thiophenes underwent the reaction more smoothly than unsubstituted and 3-substituted thiophenes
diacetals using 2,3-butane dione. These diacetals are extremely robust and can be further chemically diversified and resolved with chirality embedded in the 1,4-dioxane ring attached to the aromatic back bone as a result of the anomeric effect. These systems can serve as ligands, auxiliaries or organocatalysts for asymmetricsynthesis.