- Probing the importance of the hemilabile site of bis(phosphine) monoxide ligands in the copper-catalyzed addition of diethylzinc to N-phosphinoylimines: Discovery of new effective chiral ligands
-
(Chemical Equation Presented) The hemilabile ligand Me-DuPHOS(O) 2 has proven to be a successful ligand for the copper-catalyzed addition of diethylzinc to N-phosphinoylimines. The corresponding α-chiral amines were obtained in high yields (80-98%) and enantiomeric ratios (19.0:1 to 99.0:1 er). Furthermore, this Cu?2 catalytic system has been shown to be effective in the addition of diethylzinc to nitroalkenes and in the reduction of β,β-disubstituted vinyl phenyl sulfones. This paper describes a general structure/selectivity study in which the three ligand subunits (chiral phospholane-linker-labile coordinating group (Z)) are systematically modified and tested in the copper-catalyzed addition of diethylzinc to the N-phosphinoylimine 1 derived from benzaldehyde. This study led to the discovery of a new class of effective chiral ligands that combine a chiral phospholane unit and an achiral phosphine oxide.
- Bonnaventure, Isabelle,Charette, Andre B.
-
p. 6330 - 6340
(2008/12/22)
-
- INVESTIGATION OF THE REACTION BETWEEN DIALKYLPHOSPHINES AND CARBON TETRACHLORIDE. PART I
-
The model reaction between diethylphosphine (3a) and carbon tetrachloride leading to chloro(chloromethyl)diethylphosphonium chloride (5a) and chlorodiethylphosphine (4a) as the final product has been found to involve diethyltrichloromethylphosphine (1a) and diethylphosphine hydrogen chloride (6a) as the crucial intermediates.Process of the transformation of these compounds into the final products is a subject of our consideration. Key words: Dialkyltrichlomethylphosphines; dialkylphosphines; chlorodialkylphosphines; chloro(chloromethyl)dialkylphosphonium chlorides.
- Majewski, Piotr
-
-
- DARSTELLUNG UND NMR-SPEKTROSKOPISCHE CHARAKTERISIERUNG EINIGER DI-n-ALKYL- UND n-ALKYLARYL-CHLOROPHOSPHANE
-
A series of di-n-alkyl and n-alkylaryl chlorophosphines has been prepared by the reaction of tetraorganodiphosphines with chlorodiphenyl or dichlorophenyl phosphine and characterized by 31P and 13C NMR spectra.
- Wolfsberger, W
-
p. 167 - 174
(2007/10/02)
-
- INVESTIGATION OF THE REACTION BETWEEN DIALKYLPHOSPHINE OXIDES AND CARBONTETRACHLORIDE
-
The time dependent formation of intermediates and end products in the reaction between Et2P(O)H and CCl4 is analysed using (31)P-NMR technique.The various reaction steps are studied separately in order to elucidate the overall mechanism.A key step is the disproportionation of Et2P(O)H catalysed by Et2PCl and Et2P(O)Cl, in a cyclic process, the latter being produced initially by the reaction between Et2P(O)H and CCl4.The diethylphosphine formed during disproportionation reacts immediately with CCl4, driving the reaction through the intermediates, Et2PCl and Et2PCCl3which react with Et2P(O)OH producing Et2P(O)Cl, (Et2PO)2O, and Et2P(O)CHCl2, as end products.The influence of the substituents on rate and product yields was studied with n-propyl, n-butyl, n-octyl, and allyl as substituents in the dialkylphosphine oxide.
- Aksnes, Gunnar,Majewski, Piotr
-
p. 261 - 274
(2007/10/02)
-