F. Petit

Synthese d'aminophosphinephosphinites chiraux. Utilisation en reduction asymetrique catalytique

Abstract The chiral aminophosphinephosphinites ligands (AMPP) are directly synthesized from natural amino alcohols or by reduction of formyl esters of α-amino acids and PPh2Cl. Their cationic rhodium complexes have been found to be excellent catalysts for enantioselective hydrogenation of dehydroamino acids (ee ∼ 86%, yield ∼ 100%) for example. Asymmetric reduction of ketones can also be performed with the new alkyl AMPP* modified rhodium catalyst (ee 50%).

A useful method for the synthesis of neodymocene homogeneous catalysts for ethylene polymerization

Abstract The direct alkylation of the neodymium complex Cp 2 *NdCl 2 Li(OEt 2 ) 2 ( 1 by butylethyl-magnesium gives rise to the production of efficient homogeneous catalytic species for ethylene polymerization. The polymers are highly linear, vinyl terminated, and present narrow molecular weight distributions ( M w / M n =2). The observed molecular weights are strongly dependent on the reaction temperature and ethylene pressure. This catalytic system is shown to be more active than classical Ti/Mg heterogeneous catalysts, and even more stable in a batch reactor at 160°C and 6 bar. Experiments conducted in a pilot plant (continuous flow autoclave reactor) have been performed at 200°C and 1200 bar. These gave rise to the conclusion that the catalyst in these conditions is still able to perform the homopolymerization of ethylene with a very high productivity, even in the presence of but-1-ene in the reaction mixture.

Utilisation des ligands aminophosphinephosphinites en hydroformylation catalysée par le rhodium: amélioration de l'énantioselectivité par synthèse selective des hydrures RhH(CO)2L★2

Asymmetric hydroformylation of styrene by rhodium catalysts modified with aminophosphinephosphinite ligands has been studied. Use of either Rh4(CO)12/L★2 mixture or RhClCOL★2 in electroreduction under CO/H2, gives interesting results in respect of regio- (PhCHMeCHO/PHCH2CH2CHO) and enantio-selectivity when the ligands (1R,2S)-PPh2NMeCHMeCHPhOPPh2 and (CH3)2C(N(Me)PPh2)-HCH2OPPH2 (e.e. > 30%) are used. 1H and 31P NMR spectroscopy has indicated the occurrence of the RhH(CO)2L★2 hydride precursor, suggested to be responsible for catalysis. It is a trigonal complex having an aminophosphine function in a trans position to the hydrogen, the equatorial position being occupied by the (PO) group and the two CO moieties.

New alkylarylamidophosphinephosphinites as chiral diphosphines for asymmetric hydrogenation of activated keto compounds

Abstract Syntheses of new easily accessible chiral alkylarylamidophosphinephosphinite chelating ligands are described. Their rhodium complexes [Rh(L 2 *)Cl] 2 are highly effective precursors for the catalytic asymmetric hydrogenation of functionalized ketones. Ketopantoyllactone and N-benzylphenyl glyoxamide are converted to the corresponding alcohols up to 96 and 79.6 % ee respectively.

Asymmetric hydroformylation of styrene on aminophosphinephosphinites modified platinum catalysts

Abstract Pt(II)-aminophosphinephosphinite complexes catalyze the asymmetric hydroformylation of styrene. (S)-2-phenylpropanal with an ee of 48 % is obtained using the simple Pt(ProNOP)Cl 2 -SnCl 2 combination.

Hydrogenation asymetrique des dehydroaminoacides catalysee par des complexes rhodium-aminophosphine phosphinite. Influence de la structure des chelates

Abstract Asymmetric hydrogenation of dehydroaminoacids catalyzed by [Rh-L∗2] moieties (L∗2 - aminophosphine phosphinite) is performed with a good activity and allows optical yields of 90% in the case of acetamidoacrylic acid with the [Rh(COD)-(PPh2O) CHCH 2 CH(COR)N(PPh 2 )C H2]+ ClO4− system (R = O(CH2)2OC2H5). The product configuration and the enantioselectivity has been correlated to both the acyclic or cyclic structure of the ligand and the nature of the alkyl or aryl substituent in the chelating phosphine.

Asymmetric hydrogenation of activated keto compounds catalyzed by new chiral peralkyl-AMPP rhodium complexes

Abstract Readily available peralkyl aminophosphinephosphinite ligands (alkyl-AMPP ★ ) give neutral rhodium complexes active for the catalytic reduction of some activated ketones under atmospheric hydrogen pressure at ambient temperature (ee = 80 %).

Hydrosilylation asymetrique de l'acetophenone catalysee par des complexes au rhodium chelates par des ligands aminophosphinite et aminophosphine-phosphinite

Abstract Chiral aminophosphinite and aminophosphine-phosphinite rhodium complexes catalyse the hydrosilylation of acetophenone (e.e.43 %)

Palladium catalyzed oxidative carbonylation of alkenes by methyl formate

The use of methyl formate instead of methanol-carbon monoxide, in oxidative carbonylation of alkenes catalyzed by the system PdIICu and giving in one step olefinic ester, has been investigated. In this reaction methyl formate acts as a source of alkoxy, but an initial partial pressure of CO (up to 4–5 bar) is required in order to obtain the carbonylation products in high yield. However, CO handling can be avoided by an in situ partial decarbonylation of methyl formate catalyzed by lithium methoxide prior to the oxidative carbonylation.

Unusual, linear regioselective hydroformylation on PtL2Cl2-iron or tin catalysts

Abstract PtL2Cl2-iron or tin catalysts (L2 = diphenylphosphinobutane, DIOP…) are found to be highly selective into linear aldehydes during olefin hydroformylation, with up to 90% into hydrocinnamaldehyde and 98% into n heptanal from styrene and 1-hexene, respectively.