Maurits D. Janssen

On the way to chiral copper(I) arenethiolate catalysts for the enantioselective conjugate addition of methyl lithium and methyl magnesium iodide to benzylideneacetone

Selective conjugate addition (0 % enantiomeric excess (e.e.)) of organo- arenethiolatocuprates (from methyl lithium and 23 l-(R)-(dimethylamino)ethyl)phenyl- thiolatocopper(I), CuSAr*) to benzylideneacetone (BA) is found up to a LiMe/CuSAr* ratio of 2/l indicating the potential of the chiral SAr*-anion as non-transferable group; at higher ratios only 1,2-addition occurs. Reactions of methyl magnesium iodide with BA in the presence of a catalvtic amount of CuSAr* (9 mol%) result in exclusive conjugate addition with 57% e.e..

Application of N,S-chelating chiral zinc bis(arenethiolate) complexes as new precursor catalysts in the enantioselective addition of diethylzinc to aldehydes

Abstract The addition of diethylzinc to aldehydes in the presence of a catalytic amount of enantiomerically pure N,S -chelated bis {2-[( R )-1-(dimethylamino)ethyl]phenylthiolato}zinc, afforded the corresponding secondary alcohols in nearly quantitative yields with optical purities of up to 99 % e.e. under mild reaction conditions.

Synthesis and structural studies of phenyl(iodo)- and methyl(phenyl)palladium(II) complexes of bidentate nitrogen donor ligands

Phenylpalladium(I1) complexes of the type PdIPh(N-N), with N-N = N,N,N’,N’-tetramethylethylenediamine (tmeda) or 2,2’-bipyridyl (bpy), can be conveniently prepared in 70-95% yield by oxidative addition of iodobenxene to bis(dibenzylideneacetone)palladium(0) in the presence of the appropriate nitrogen donor ligand. The bromo analogues were obtained in only S-12% yield in this way. The complex PdIPh(tmeda) (la) reacts readily with MeLi to give PdMePh(tmeda) (3) in 88% yield, whereas PdIPh(bpy) (la) gives PdMePh(bpy) (4) and PdMe,(bpy) in varying ratios. The formation of PdMe,(bpy) was found to result from the synergistic action of lithium iodide and methyllithium. Pure PdMePh(bpy) (4) was obtained in 82% yield via ligand-exchange from PdMePh(tmeda) (3). The crystal structures of PdIPh(N-N) (la, 2a) and PdMePh(N-N) (3, 4) complexes were determined by X-ray diffraction studies. The results show that the phenyl group is always oriented perpendicular to the coordination plane aroutd palladium, with the largest deviation found for 3 (14.3(2)“). The Pd-N bond distances in the tmeda complexes (2.127(6)-2.210(3) A) are larger than those in the bpy-coordinated complexes (2.870(8)-2.144f8) A). Similarly, the Pd-CfMe) bond distances (2.5703(8) and 2.575(l) & are larger than the Pd-C(Ph) bond distances (1.985(3)-1.996tlO) A)>.

Monomeric bis(η2-alkyne) complexes of (η1-mesityl)copper(I) and (η1-mesityl)silver(I) obtained from a bis(alkynyl)titanocene; X-ray structure of [(η5-C5H4SiMe3)2Ti(CCSiMe3)2]Cu(η1-Mes)(Mes = C6H2Me3-2,4,6)

Polynuclear mesitylcopper and mesitylsilver react with [(η5-C5H4SiMes3)2Ti(CCSiMe3)2]1 to afford the monomeric complexes [1·Cu(η1-Mes)]2, and [1·Ag(η1-Mes)]3, in which both alkyne moieties of the 3-titanopenta-1,4-diyne unit are η2-coordinated to a MesCu(Ag) unit.

Highly selective hydrocarboxylation of styrene with oxalic acid or water using palladium ortho-amino arenethiolates with intramolecular coordinating nitrogen Lewis bases

Abstract Under mild conditions and in the presence of a catalytic amount of an S,N-chelated palladium ortho-amino arenethiolate complex, styrene reacts with carbon monoxide and oxalic acid or water to selectively give 2-phenylpropanoic acid in high yield.

BISPHENOLATE IRON(II) COMPLEXES WITH INTRAMOLECULARLY COORDINATING NITROGEN LEWIS BASES

The synthesis and characterisation of a novel Fe(II) bisphenolate complex [Fe(OC6H4CH2NMe2-2)2]2 (1) from [Na(OC6H4CH2NMe2-2)] and anhydrous FeCl2 is reported. The solid state structure has been elucidated by single crystal X-ray analysis and shows a dimeric structure with two bridging and two terminal phenolate ligands. Compound 1 reacts with pyridine to form the adduct [Fe(OC6H4CH2NMe2-2)2(py)2 ]( 2). Similarly, 2 equiv. of [Na(OC6H2(CH2NMe2)2-2,6-Me-4)] were reacted with FeCl2 and the thus in situ prepared ‘[Fe(OC6H2(CH2NMe2)2-2,6-Me-4)2]n ’( 3) was reacted with pyridine to form the adduct [Fe(OC6H2(CH2NMe2)2-2,6-Me-4)2(pyr)2 ]( 4). Compound 4 was characterised by single crystal X-ray analysis. Attempts to use these compounds as catalysts in the oxidation of cyclohexane with t-butylhydroperoxide (cat.:C6H12:t-BuOOH 1:1000:100) resulted in the direct formation of brown coloured products, probably as a result of irreversible oxidation of 1, 2, 3 and 4, respectively. No cyclohexanol or cyclohexanone was formed.

A second polymorph of 2,2'-bipyridyl-(methyl)(phenyl)palladium(II)

The crystal structure of a second polymorph of [Pd(CH 3 )(C 6 H 5 )(C 10 H 8 N 2 )], containing four crystallographically independent molecules, is presented and compared with the structure of the previously reported polymorph [Markies et al. (1994). J. Organomet. Chem. 482, 191-199] containing only one crystallographically independent molecule. In both polymorphs molecules lie in infinite stacks, surrounded by six similar stacks ; the main difference between the two polymorphs is about 23° in the tilt angle of the coordination plane with reference to the stacking direction.

1-tert-Butyl-2-(tert-butylaminomethylidene)-3-pyrrolidinone, C13H24N2O

The eneamine moiety on the pyrrolidinone rig is coplanar to the carbonyl function, with an E configuration stabilized by an intramolecular N-H...O bond