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Aldol condensations on α,β-epoxyaldehyde having a remote alkoxy group have been realized. A rationalization of the outcome of this condensation is discussed, relying on the dominant conformers revealed by molecular modeling of anti and syn γ,δ-epoxy β-hydroxyesters and their NMR and IR spectrostroscopic properties.

Aldol condensations on α,β-epoxyaldehyde having a remote alkoxy group have been realized. A rationalization of the outcome of this condensation is discussed, relying on the dominant conformers revealed by molecular modeling of anti and syn γ,δ-epoxy β-hydroxyesters and their NMR and IR spectrostroscopic properties.

Reacting Zn(CF3SO3)2 with the title ligand (ON) yields a 1:2 complex which precipitates from methanol as the [Zn(ON)2(CH3OH)2](CF3SO3)2 salt. The crystal structure of this complex (P11/c, a=13.711(2), b=10.401(2), c=16.358(2) A, β=124.27(1)°, R=0.059, 1918 observed reflections) reveals the presence of a centrosymmetric, nearly octahedral, complex cation. The all-trans configuration about Zn2+ is achieved by two methanol hydroxyl groups and two bidentate ligands bonded via their pyridyl nitrogens and amide oxygens. The amide group nitrogen is not coordinated to the metal, but it forms an NH.…O hydrogen bond to the CF3SO3− counterions. The influence of the amide substituent on the structure is discussed on the basis of comparisons with the [Zn{N-(2-pyridyl)acetamide}2(H2O)2]2+ ion containing a similar amidopyridine chelate ring.

5′-C-substituted nucleosides with an hydroxyalkyl chain are synthesized. The stereochemistry of the new stereogenic center is defined. After introduction of a tosyl group, dimer models are prepared to evaluate the conjugation with amines used as nucleophiles.

The nucleophilic additions of hindered organometallic compounds to polycyclic ketones with trans ring junctions involve predominant axial attack when flattening of the ring containing the carbonyl group occurs. The influence of nucleophile structure (O-Por C-metallated character) on equatorial or axial attack is discussed.

Organomercuric compounds of the general formula and [RCOCH(R′)] 2 Hg, obtained from three ketones, 2,2-dimethyl 3-pentanone, 1-mesityl 1-propanone and 1-mesityl 1-ethanone, have been studied by 13 C and 199 Hg NMR techniques. Coupling constants J (CHg) and J (HgH) are consistent with C-metalated species; in each case the values of δ(C(2)) and J (C(2)H) observed are higher than expected for purely sp 3 carbon. The contribution of O-metalated species and hyperconjugative effects are discussed. For two dioxomercuric compounds (R′  Me, R  t-Bu, mesityl) the existence of diastereoisomers is suggested from 199 Hg NMR data.

Interactions between boric acid and Shikimic acid and quinic acid or (and) its methyl esters, have been studied by means of 11B and 13C NMR, in aqueous solution, and in presence of potassium hydroxyde. Monocyclic and spiranic borates have been isolated allowing a better understanding of the equilibria which take place.

The behavior of metallated imines and hydrazones toward α,β-unsaturated ketones was studied, using different reaction times and temperatures. Dissociation of the functional group (imine or hydrazone) in the adducts and regioselectivity in their condensation reactions are discussed. The first example of reversible addition to the carbonyl group of an enone is demonstrated for the reaction between trans chalcone and

The ZnBr2 complexes of the four title sulfinamoylesters were formed and investigated by NMR and i.r. techniques. The stoichiometry of the complexes greatly depends on the position of the amino or hydroxyl substituents on the aromatic ring. Nevertheless, the occurrence of a tetracoordinated zinc atom is suggested for all the complexes.

The zinc(II) complexes of the title sulfinamoyl compounds L 2 ·ZnX 2 (X = Cl, Br) were prepared and studied by NMR and i.r. methods. All the complexes have a tetrahedral [O 2 X 2 ] coordination and NH . . X hydrogen bonding.

Tert -butyl N-aryl sulfinamoyl acetates are hydrolysed in aqueous basic media following a bimolecular elimination process, via an intermediate sulfine species. The use of sulfinamoyl compounds as irreversible inactivators for zinc-metallo-enzymes is emphasized.

Association capabilities of oxobromomercuric and dioxomercuric compounds I and II have been investigated by cryoscopic methods, 1 H NMR, IR and Raman spectroscopy. The association degree n is concentration dependent for I in C 6 H 6 while no variation of n is observed in the case of II for which the value of n is close to one. Similarly 1 H NMR data show diminuation of 2 J (HgH) and 3 J (HgH) upon solution of I in C 6 D 6 or CDCl 3 while no modification of 2 J and 3 J is noticed for II. Using C 6 D 6 as solvent, important shielding of δ(CH) and δ(CH 3 ) is found in the spectra; these effects are smaller for δ(CH 3 ) than for δ(CH) and less clear for II than for I. IR and Raman spectra of I and II in the solid state show associative intermolecular interactions Hg…Br (in I), Hg…O intramolecular interactions and a linear structure of CHgC in II. The splitting of v (CO) frequencies for solutions of I and II in C 6 D 6 is attributed to Fermi resonances. These results, in connection with the variation of n in I, are consistent with an equilibrium between monomeric and associated HgBr species for the oxobromomercuric compound I and with an intramolecularly associated monomer for the dioxomercuric compound II.