- Azadiphosphaindane-1,3-diyls: A Class of Resonance-Stabilized Biradicals
-
Conversion of 1,2-bis(dichlorophosphino)benzene with sterically demanding primary amines led to the formation of 1,3-dichloro-2-aza-1,3-diphosphaindanes of the type C6H4(μ-PCl)2N-R. Reduction yielded the corresponding 2-az
- Bresien, Jonas,Michalik, Dirk,Schulz, Axel,Villinger, Alexander,Zander, Edgar
-
p. 1507 - 1512
(2020/12/01)
-
- Easy Access to Phosphine-Borane Building Blocks
-
In this paper, we highlight the synthesis of a variety of primary phosphine-boranes (RPH2?BH3) from the corresponding dichlorophosphines, simply by using Li[BH4] as reductant and provider of the BH3 protecting group. The method offers facile access not only to alkyl- and arylphosphine-boranes, but also to aminophosphine-boranes (R2NPH2?BH3) that are convenient building blocks but without the protecting BH3 moiety thermally labile and notoriously difficult to handle. The borane-protected primary phosphines can be doubly deprotonated using n-butyllithium to provide soluble phosphanediides Li2[RP?BH3] of which the phenyl-derivative Li2[PhP?BH3] was structurally characterized in the solid state.
- de Jong, G. Bas,Ortega, Nuria,Lutz, Martin,Lammertsma, Koop,Slootweg, J. Chris
-
p. 15944 - 15952
(2020/10/28)
-
- Modular chiral bidentate phosphonites: Design, synthesis, and application in catalytic asymmetric hydroformylation reactions
-
A new class of C2-symmetric chiral bidentate phosphonite ligands has been synthesized in moderate to good yields from readily available starting materials. Application of these air-stable chiral phosphonites in the Rh I-catalyzed asymmetric hydroformylation of styrene derivatives, vinyl acetate, and allyl cyanide afforded the corresponding chiral aldehydes with high regio- and enantioselectivities under mild reaction conditions. The modular nature of the ligands allows fine-tuning of the selectivities through judicious modifications of the substituents on the ligand backbone. X-ray structural analysis of the catalyst precursor suggested that the steric hindrance caused by the protruding remote substituents of the ligands into the vicinity of the metal center might be an important factor for the enantio-control of the reaction, whereas the sense of asymmetric induction can be rationalized on the basis of a trigonal-bipyramidal transition state diagram.
- Zhao, Baoguo,Peng, Xingao,Wang, Zheng,Xia, Chungu,Ding, Kuiling
-
supporting information; experimental part
p. 7847 - 7857
(2009/11/30)
-
- Template controlled synthesis of a coordinated [11]ane-P2C NHC macrocycle
-
Rhenium complex [5]Cl with the coordinated [11]ane-P2C NHC macrocycle was obtained by a metal template controlled ring formation reaction; in this reaction a coordinated NH,NH-stabilised imidazolidin-2-ylidene ligand was connected vi
- Kaufhold, Oliver,Stasch, Andreas,Edwards, Peter G.,Hahn, F. Ekkehardt
-
p. 1822 - 1824
(2007/12/27)
-
- 2,5-Dimethyl-3,4-bis[(2R,5R)-2,5-dimethylphospholano]thiophene: First member of the hetero-DuPHOS family
-
The 2,5-dimethyl-3,4-bis[(2R,5R)-2,5-dimethylphospholano]thiophene (UlluPHOS), a new thiophene-based analogue of (R,R)-1,2-bis(phospholano)benzene (Me-DuPHOS), was synthesized, geometrically and electronically characterized, and employed as ligand of Rh and Ru in some standard hydrogenation reactions of prostereogenic functionalized carbon-carbon and carbon-oxygen double bonds. The synthesis of UlluPHOS is much easier than that provided for Me-DuPHOS. UlluPHOS and Me-DuPHOS display very similar geometries, while the electronic availability of the former is higher than that exhibited by the latter. The Rh and Ru complexes of UlluPHOS produced excellent enantiomeric excesses (98.9-99.5%) in the hydrogenation of N-acetyl-α-enamino acids and reaction rates higher than those found when employing the analogous complexes of Me-DuPHOS.
- Benincori, Tiziana,Pilati, Tullio,Rizzo, Simona,Sannicolo, Franco,Burk, Mark J.,De Ferra, Lorenzo,Ullucci, Elio,Piccolo, Oreste
-
p. 5436 - 5441
(2007/10/03)
-
- Polymer-supported phosphorus ligands for catalysis
-
Novel phosphine and phosphine oxide ligands are prepared using polymeric supports. These compounds can be easily cleaved from the support, and along with the corresponding supported compounds, used as ligands in the preparation of novel, metal-complexed catalysts. The ligands are obtained by combinatorial synthesis. A process for preparing coumarin by contacting salicylaldehyde with an acrylate is also provided.
- -
-
-
- Polymer-supported phosphorus ligands for catalysts
-
Novel phosphine and phosphine oxide ligands are prepared using polymeric supports. These compounds can be easily cleaved from the support, and along with the corresponding supported compounds, used as ligands in the preparation of novel, metal-complexed catalysts.
- -
-
-
- BINOL-based diphosphonites as ligands in the asymmetric Rh-catalyzed conjugate addition of arylboronic acids
-
matrix presented BINOL-based diphosphonites having achiral backbones are useful ligands in the Rh-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds. The nature of the achiral backbone determines the direction and degr
- Reetz, Manfred T.,Moulin, Dominique,Gosberg, Andreas
-
p. 4083 - 4085
(2007/10/03)
-