Stéphane Sabelle

Enantioselective Synthesis of α‐Amino Acids and Monosubstituted 1,2‐Diamines by Conjugate Addition of 4‐Phenyl‐2‐oxazolidinone to Nitroalkenes

The addition of the potassium salt of (R)- or (S)-4-phenyl-2-oxazolidinone to monosubstituted nitroalkenes proceeded with very good diastereoselectivity. Several of the addition products were converted into α-amino acids and monosubstituted 1,2-diamines of high enantiomeric purity.

McMurry intermolecular cross-coupling between an ester and a ketone: scope and limitations

Abstract In the course of our studies towards the synthesis of a dioxetane bearing chemiluminescent probe for the detection of thiols, we were faced with the synthesis of sterically hindered benzylic enol ethers. This issue was solved via the use of an intermolecular McMurry cross-coupling between an ester and a ketone. In this article, together with the synthesis of the chemiluminescent probe, the scope and limitations of this low valent titanium based carboncarbon double bond formation are discussed.

Enantioselective synthesis of α-amino acids from nitroalkenes

The products of the conjugate addition of (R)-4-phenyl-2-oxazolidinone on monosubstituted nitroalkenes were converted into d-α-amino acids of high enantiomeric purity.

Solvation Accounts for the Counterintuitive Nucleophilicity Ordering of Peroxide Anions

The nucleophilic reactivities (N, sN ) of peroxide anions (generated from aromatic and aliphatic peroxy acids or alkyl hydroperoxides) were investigated by following the kinetics of their reactions with a series of benzhydrylium ions (Ar2 CH+ ) in alkaline aqueous solutions at 20 °C. The second-order rate constants revealed that deprotonated peroxy acids (RCO3- ), although they are the considerably weaker Brønsted bases, react much faster than anions of aliphatic hydroperoxides (ROO- ). Substitution of the rate constants of their reactions with benzhydrylium ions into the linear free energy relationship lg k=sN (N+E) furnished nucleophilicity parameters (N, sN ) of peroxide anions, which were successfully applied to predict the rates of Weitz-Scheffer epoxidations. DFT calculations with inclusion of solvent effects by means of the Integral Equation Formalism version of the Polarizable Continuum Model were performed to rationalize the observed reactivities.