Isabelle Canet

Enantioselective synthesis of (−)-indolizidine 167B

Abstract The enantioselective total synthesis of (−)-indolizidine 167B is described. The key step is the intramolecular cyclization of the chiral N -acyliminium ion 6 . Indolizidine 167B was obtained in 7 steps and 17% yield from ethyl ( R )-3-aminohexanoate, with an enantiomeric excess of 93%.

Design and synthesis of chiral peptidic nucleic acids

Due to the increasing interest in the use of oligonucleotide analogues as antisense and antigene drugs, we designed a chiral analogue constituted of a peptidic frame bearing nucleobases in suitable positions (C-PNA). We recently reported the synthesis of four nonnatural α-amino acids with the DNA bases in the lateral chain. In this paper we present an improved synthesis of the Fmoc monomers and their polymerisation to polypeptidic oligonucleotide analogues using a modification of the standard protocol for solid phase peptide synthesis.

Molecular design of calcimycin (A23187) evidenced by the complexing behaviour of its 4-bromo and 19-demethyl analogues

An original comparison of the complexing properties of calcimycin (A23187) and its 4-bromo and 19-demethyl analogues with the alkaline earth cations, Mn2+ and Zn2+, gives new insight on the molecular design of this universally used calcium ionophore.

Unusual structure of the dimeric 4-bromocalcimycin–Zn2+ complex

The X-ray structure of [Zn(4-bromocalcimycin)2 x H2O] complex shows two highly different conformations of the ligand in the dimeric association, unusual in this ionophore family.

FACILE AND PERFORMANT ENANTIOMERIC EXCESS ANALYSIS OF DIENE IRON TRICARBONYL COMPLEXES THROUGH DEUTERIUM NMR

Abstract Complete and accurate stereoisomeric analysis of chiral [(η 4 -dienal)Fe(CO) 3 ] complexes can be performed by deuterium NMR in a chiral (polypeptide-dichloromethane) solvent, through reduction of aldehydes to the corresponding deuteriated alcohols. This new application of Courtieus method opens an efficient entry to stereoisomeric analysis of chiral organometallics.

Electrochemical Reduction in an Aprotic Medium of New Functionalized Amphiphilic Molecules Derived from Sugars: Stereoselective Pinacolization and an Example of a Glycosidic Carbon‐Oxygen Bond Cleavage

Electroreducible amphiphilic aromatic ketones derived from D-glucose and D-glucofuranurono-6,3-lactone (D-glucurone) have been synthesized by Schmidt condensation and reaction of the unprotected lactone with the appropriate substrates, respectively. The macroscale electrolyses of the glucose derivatives, performed in an aprotic solvent (DMF), yield the pinacols possessing two glycosidic side chains. Under the same conditions of electrolysis with the D-glucurone derivative, the glyosidic carbon-oxygen bond is cleaved. The use of a redox mediator (couple anthracene−•/anthracene) has demonstrated that a glucosidic bond can be reduced by a homogeneous electron transfer. In the presence of a proton donor the expected D-glucuronic pinacol is obtained. The radical-radical coupling involves the formation of two chiral centers. The diastereo- and the enantioselectivity of the reaction have been studied by 1H- and 2H-NMR spectroscopy, respectively.