Maryse Gouygou

X-Ray characterization of enantiomerically pure 1,1′-diphenyl-3,3′,4,4′-tetramethyl-2,2′-biphosphole: a ligand with axial and central chirality

The stereochemical analysis and characterization of diastereoisomers of 1,1′-diphenyl-3,3′,4,4′-tetramethyl-2,2′-biphosphole having axial and central chirality reveal the potential interest of this ligand for asymmetric catalysis.

Reaction of heterocumulenes RNCNR and RPCPR with a di-iron aminocarbene complex

Abstract Reaction of Rue5f8Nue5fbCue5fbNue5f8R (Rue5fb p -Me-C 6 H 4 ) and Rue5f8Pue5fbue5fbCue5fbPue5f8R (R=2,4,6- t Bu 3 C 6 H 2 ) with the di-iron aminocarbene complex [Fe 2 (CO) 7 {1μ-C(Ph)C(NEt 2 )}] ( 1c ) gave corresponding complexes [Fe 2 (CO) 6 {C(Ph)C(NEt 2 )C(NC 6 H 4 Me)N (C 6 H 4 Me)}] ( 2 ) and [Fe 2 (CO) 6 {C(Ph)C(NEt 2 )C(PC 6 H 2 t Bu 3 )P(C 6 H 2 t Bu 3 )}] ( 4 ), resulting from a coupling reaction with carbon-carbon bond formation. [Fe 2 (CO) 5 (CNC 6 H 4 Me){C(Ph)C(NEt 2 )N(C 6 H 4 Me)}], complex 3 , obtained in the reaction with Rue5f8Nue5fbCue5fbNue5f8R, resulted from Cue5fbN bond rupture insertion of a nitrene fragment into the Feue5fbC bond. Complexes 2–4 were characterized by X-ray diffraction. The different geornetries of complexes 2 and 4 are discussed. The formation of these complexes may be explained by cycloaddition on the Fe ue5fbC metal-carbene bond.

DIPHOSPHIRANE AND 1,3-DIPHOSPHAALLYL ANION : GEOMETRY AND BONDING

Abstract The unsymmetrical diphosphirane 2a , obtained by addition of dichlorocarbene to the corresponding diphosphene ArPue5fbPTsi (Ar ue5fb 2,4,6,-tri-tert-butylphenyl; Tsi ue5fb tris(trimethylsilyl)methyl) presents a structure with the shortest Pue5f8P bond (2.117 A) ever observed in the diphosphirane series, and a torsion angle (Ar)CPPC(Tsi) close to 180° (177.0°). A shortening of intra- and extracyclic Pue5f8C bonds, as well as of CCl bonds, is also observed comparative to the symmetrical diphosphirane 1a . Such short bonds can account for the special chemical behaviour of 2a . The anionic ring opening of the diphospharine 1c leads to the stable 1,3-diphosphaallyl anion 7c . The equivalence of the two phosphorus atoms and the existence of a Pue5f8Li coupling constant of 41 Hz is an argument for a σ-allytic structure in solution.