M. Pierrot

Oxydation et addition des dihalocarbènes sur le β-himachalène

Resume Reaction of β-himachalene with one equivalent of dihalocarbene, KMnO 4 or m -CPBA gives regio- and stereospecifically one product resulting from the attack of the C6 C7 double bond. The molecular structure shows that this attack occurs on the α face of this double bond.

Copper(II)/H2O2-Mediated DNA cleavage: Involvement of a copper(III) species in H-atom abstraction of deoxyribose units

A new bis-amido-copper(II) complex 2 has been prepared. In the presence of reducing agents (ascorbate or DTT) under air atmosphere or hydrogen peroxide, complex 2 exhibited interesting nuclease activities in the 1-10 microM concentration range. For explaining the activity observed with hydrogen peroxide, we propose the occurrence of a bis-amido-copper(III) intermediate and an oxidation mechanism involving a H-atom abstraction of deoxyribose moieties of DNA.

Copper monooxygenase models: hydroxylation reactions resulting from dioxygen activation by copper(I) complexes

We describe the synthesis and reactivity of new mononuclear copper(I) complexes 4a–c, which can be considered to be copper monooxygenase models and can be used to achieve hydroxylation of aliphatic C–H bonds by dioxygen activation.

REGIOSPECIFIC SYNTHESIS OF A NEW CHIRAL N-SUBSTITUTED PYRAZOLE USING A SESQUITERPENE HYDROCARBON

ABSTRACT Treatment of β-enaminone 4 with 2-hydrazinopyridine gives a regiospecific formation N-substituted pyrazole 6. Enaminone 4 was prepared for the first time by reacting enone 3 with sodium azide in acidic medium. The structural assignment of 2, 3, 4, 5 and 6 is based upon 1H, 13C NMR spectroscopy, mass spectrometry and X-ray structural analyses.

Ozonolysis; intramolecular trapping of the Criegee intermediate X-ray analysis and anomeric effect in a 6-hydroxy-3-methoxy-1,2-dioxane

Abstract Ozonolysis of (1-methyl-2-propen-yl)-pulegol in methanol solution gives an endoperoxide bearing the 6-hydroxy-3-methoxy-1,2-dioxane ring. X-Ray analysis reveals the presence of endo - and exo -anomeric effect.

(1S,3R,8S,9S,10R)-2,2-Dichloro-9,10-epoxy-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodecane and (1S,3R,8S,10R)-2,2-dichloro-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodecan-9-one

The stereochemistries of the title compounds, both C(16)H(24)Cl(2)O, have been established by X-ray diffraction. In both structures, the seven-membered ring adopts the same conformation, whereas the six-membered ring shows an envelope conformation in the epoxydodecane structure and a boat conformation in the dodecan-9-one structure.

A mixed nickel-lithium pyrophosphate, LiNi1.5P2O7

The title compound, dilithium trinickel bis(diphosphate), is composed of [P2O7] layers parallel to the crystallographic plane (001), separated by chains of [NiO6] octahedra. The coordination polyhedra of the Li+ ions link the [P2O7] groups and the [NiO6] octahedra, and so ensure the cohesion of the structure.

Synthesis and crystal structures of a series of amide copper(II) complexes

The synthesis and structural determination by X-ray crystallography of four amide copper(II) complexes has been performed: [Cu{OC[(CH2)2N(CH2C6H4X)(CH2CH2C5H4N)]NH(CH2)nPh}(solv)][CF3SO3]2(X = H, solv = H2O, n= 2 1 or 1 2; X = OH, solv = H2O, n= 2 3; solv = MeCN, n= 1 4). In all complexes the co-ordination around the copper atom is a more or less distorted square-based pyramid where the three ligands of the square are unchanged: one oxygen atom of the amide group and two nitrogen atoms of the pyridine nucleus and of the tertiary amine. The fourth ligand is a water molecule (1–3) or an acetonitrile solvent molecule (4). The axial ligand is the oxygen atom of the phenolic group in complexes 3 and 4, while in 1 and 2 this site is occupied by an oxygen atom of a triflate counter ion.

Reductive coupling of ()-(+)-carvone and (+)-camphor by the tiCl4-mg reagent. X-ray crystal structure of (+)-(1S, 5R, 1′S, 5′R)-carvone pinacol ☆

Abstract The reductive coupling of ( R )-(+)-carvone by TiCl 4 -Mg-tBuOH leads to (+)-(1 S , 5 R , 1′ S , 5′ R )-carvone pinacol 3 (70 %). In presence of pentane, (−)-(1 R , 5 R 1′ R 5′ R )-carvone pinacol 4 (50 %) and ketol 5 (15 %) are isolated. Isoborneol (58 %) and borneol (32 %) result of the reduction of (+)-camphor with the same reagent.

SYNTHESIS OF ENANTIOMERICALLY PURE CIS- AND TRANS-1,2-DIAMINOINDANES

Abstract The four isomers of cis - and trans -1,2-diaminoindanes 5 and 11 were prepared in three steps and high enantiomeric excess by a key lipase-catalyzed selective transesterification of racemic cis -2-azido-1-indanol and trans -1-azido-2-indanol, respectively.