Alexei I. Polosukhin

New chiral phosphite ligands bearing sp2-nitrogen: complexation properties and palladium(II)-catalysed enantioselective allylic alkylation

Abstract New homochiral P , N -bidentate phosphite-type ligands containing sp 2 -nitrogen were synthesised and their complexation with Rh(I) and Pd(II) atoms was investigated. The X-ray crystal structure of one of the chelate chlorocarbonyl rhodium complexes was obtained. E.e.s of up to 85% were attained in the Pd-catalysed allylic substitution reaction using the new P , N -ligands.

Easily Accessible Chiral P,N-Bidentate Aryl Phosphites, Their Complexation and Application in Enantioselective Allylic Alkylation, Sulfonylation and Hydrosilylation

New chiral P,N-hybrid aryl phosphites have been obtained by one-step phosphorylation of amino and imino alcohols. Complexation of the new ligands with [Rh(CO)2Cl]2, [Pd(COD)Cl2] and [Pd(allyl)Cl]2 was found to give chelate complexes [Rh(CO)Cl(η2-P∩N)], [PdCl2(η2-P∩N)] and [Pd(allyl)(η2-P∩N)]+Cl−, respectively. With these new P,N-ligands, up to 82% ee enantioselectivity was achieved in the Pd-catalysed alkylation of ethyl 3-penten-2-yl carbonate with dimethyl malonate, up to 80% ee in the Pd-catalysed sulfonylation of methyl 3-penten-2-yl carbonate with sodium p-toluenesulfinate, and up to 50% ee in the Rh-catalysed hydrosilylation of acetophenone with diphenylsilane. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

New amino-, imino- and oxazolinophosphites based on 1,1′-bi-2-naphtol: coordination and catalytic properties

Abstract A series of the new chiral BINOL-based phosphite P , N -hybrid ligands was prepared. The coordination behavior of all the ligands was studied and the neutral complexes [Rh(CO)Cl(P ∧ N)] were synthesized in order to characterize a degree of the electronic non-symmetry of donating centers. Also the neutral and cationic complexes cis -[PdCl 2 (η 2 -P ∧ N)], cis -[PdCl 2 (η 1 -P ∧ N) 2 ], cis -[PdCl(η 2 -P ∧ N)(η 1 -P ∧ N)] + Cl − , [Pd(allyl)(η 2 -P ∧ N)] + X − (X − =Cl − , BF 4 − ) were obtained and characterized. The new P , N -hydrid ligands gave up to 81% ee in the enantioselective Pd-catalyzed alkylation of 3-penten-2-yl carbonate by dimethyl malonate and up to 60% ee in the Rh-catalyzed hydrosilylation of acetophenone and acetylferrocene by diphenylsilane.

Synthesis and properties of pentacoordinated phospha derivatives of iso-leucinol A rare example of using of hydrophosphoranes as ligands in asymmetric catalysis

Abstract New bicyclic (1) and tricyclic (2a) hydrophosphoranes have been synthesized from iso-leucinol. Complexation of bicyclic hydrophosphorane 1 with [PdCl2(COD)], [PdCl2(RCN)2] and [Pd(allyl)Cl]2 has been found to give chelate products [PdCl2(L)] and [Pd(allyl)(L)]+Cl− containing an “open” form of the phosphorane. Tricyclic hydrophosphorane 2a, as well as its homologue 2b, forms metal complexes with P-monodentate binding of a hydrophosphorane, phosphoranide or “open” form of the ligand. Up to 74% ee has been achieved in the Pd-catalyzed alkylation of 1,3-diphenylallyl acetate with dimethyl malonate using 1 and 2a and 2b as chiral ligands.

Quincoridine-based aminophosphite ligands and their Rh(I) and Pd(II) complexes

New chiral P,N-bidentate ligands containing a quincoridine fragment with a configuration-stable N-donating center were obtained. Coordination of the ligands to Rh(I) and Pd(II) atoms was carried out. Chlorocarbonyl rhodium and dichloride palladium complexes were found to be cis-chelates with P,N-bidentate ligands.

Complexation of hydrophosphoranes: possible mechanism and coordination activity

Complexation of (4S,9S)-4,9-diethyl-2,11-dioxa-5,8-diaza-1l 5 -phosphatricyclo[6.3.0.0 1.5 ]undecane (1) and 3,3,8,8-tetramethyl1,6-dioxa-4,9-diaza-5l 5 -phosphaspiro[4,4]nonane (2) with [Rh(CO)2Cl]2; 2,3,7,8-dibenzo-1,6-dioxa-4,9-diaza-5l 5 -phosphaspiro[4,4]nonane (3) with [Rh(CO)2Cl]2 and [MCl2(COD)] (M Pd, Pt); (2S,7S)-2,7-dimethyl-1,4,6,9-tetraoxa-5l 5 -phosphaspiro[4,4]nonane (4) with [Rh(CO)2Cl]2 and [PdCl2(COD)] has been studied. The products have been characterized by 1 H-, 2 H-, 13 C-, 31 P-NMR, IR spectroscopy, laser desorption mass spectrometry and X-ray photoelectron spectroscopy. A possible mechanism for hydrophosphoranes complexation is discussed. A correlation between Lewis basicity and coordination activity has been found for ligands 1‐3. Phosphorane 4 was shown to coordinate by means of the P(III)-tautomer.

Phosphite derivatives of (2R)-2-pyrrolidin-1-yl-butan-1-ol: synthesis, chelation with rhodium(I) and testing in the palladium-catalysed allylic alkylation

A series of chiral phosphite-type ligands with pyrrolidine moieties was synthesised. The compounds form chelate complexes upon reaction with [Rh(CO)2Cl]2. The new ligands were tested in Pd-catalysed enantioselective allylic alkylation giving up to 61% ee under standard conditions.

Complexes of Rh(I) with phosphite derivatives of codeine

Abstract New complexes of Rh(I), [RhCl(CO)(μ-L)]2 and AcacRh(CO)L, have been obtained with L=1,3,2-dioxaphosphorinane containing an exocyclic codeine fragment. The complexes were characterized by 1H-, 13C-, 31P-NMR, IR spectroscopy, plasma desorption mass spectrometry, X-ray photoelectron spectroscopy and sedimentation analysis. It was found that the chlorocarbonyl rhodium complex is a dimer with the bridge-type P,N-bidentate ligands coordinated in the ‘head to tail’ mode. The same ligand in the acetylacetonate complex was found to be P-monodentate.

P,N-Bidentate Phosphorus Derivatives of (S)-Prolinol

AbstractPhosphorylation of (S)-prolinol with P(NEt2)3was used to synthesize aminophosphite (2R,5S)-