Jean-Christophe Plaquevent

Enantioselective electrophilic bond construction to the α-carbon of α-aminoacids

Abstract In this report, we describe three possibilities for aminoacid synthesis using an enantioselective electrophilic process. Thus, enantioselective carboxylation, alkylation and protonation of Schiff bases yield optically active aminoacids with e.e. up to 76%.

4-Phenylbenzylidene benzylamine: A new and convenient reagent for the titration of solutions of lithium alkyls and metal amides

Abstract 4-Phenylbenzylidene benzylamine is shown to be an excellent reagent for the determination of solutions of lithium alkyls and metal amides. The azaallyl anion produced is deep blue in tetrahydrofuran, and fades to pale yellow via red when titrated with 2-butanol in xylene. The method can also be used for estimation of the dryness of the solvent. The crystalline indicator is easily prepared, stored and handled.

Enantioselective dehydrohalogenation via asymmetric deprotonation by chiral lithium amides: Deracemization of a compound bearing a chiral axis

Abstract Chiral lithium amides exert asymmetric induction in dehydrohalogenation reactions leading to axially dissymmetric compounds. Thus the deracemization of 4-tert-butyl-cyclohexylidene acetic acid 1 via the prochiral hydrochlorinated intermediate 2 is reported with e.e. as high as 82 %.

Thiazolinium and imidazolium chiral ionic liquids derived from natural amino acid derivatives

Summary.Starting from commercially available amino acid derivatives, two novel families of chiral ionic liquids having either a thiazolinium or an imidazolium cation were prepared by simple and straightforward procedures in good overall yields. The properties of these new salts can be finely tuned by careful selection of the anion and the cation.

Enantioselective α-selenenylation of 2-phenylpropanal

Abstract The parameters (media, temperature, structures of the reactants) relative to the enantioselective α-selenenylation of 2-phenylpropanal with chiral areneselenenamides have been studied. Enantiomeric excesses as high as 60 % have been observed. Recrystallization yielded an α-seleno-aldehyde in an optically pure form.

Réduction régiospécifique des bipyridines

Abstract A method for the specific reduction of bipyridines through the use of the N - oxo derivatives is described.

Reactivity of α-arylseleno-aldehydes towards halogens and benzeneselenenyl chloride

Abstract Chlorination of α-seleno-aldehydes bearing an α-hydrogen gives selenium dichlorides which decompose into α-chloro α-seleno-aldehydes and α-chloroenal. Bromination, in all cases, and chlorination for the other α-seleno-aldehydes lead to the α-halogenoaldehydes.

Amidures de lithium chiraux; β-élimination de trityllithium à partir d'un amidure de lithium

Abstract The synthesis of a chiral secondary amine bearing a NCH2-trityl moiety is described. The formation of the corresponding lithium amide results in the β-elimination of trityllithium, leading to an intermediate methyleneamine, which can react with nucleophiles.

Studies on the structural feature of S'1 subsite of neprilysin (EC.3.4.24.11): Stereochemical requirement for the enzyme-inhibitor docking process

Abstract The preferred conformation of thiorphan during the inhibitor-neprilysin docking process was investigated. A series of achiral inhibitors were tested. This study led to the design of a potent inhibitor, in which the ethylenic bond bears the aryl residue of P′1.