Bernd Schäfer

A new mild method for the synthesis of amidines

Abstract A new method for the synthesis of amidines is presented using N-acetylcysteine as a catalyst. The key advantage of this new method is that it is compatible with a large number of functional groups. It allows the synthesis of amidines in complex molecules containing acid-labile groups, base-labile centers of asymmetry or functional groups sensitive to hydrogenation.

DIASTEREOSELECTIVE PROTONATION AFTER THE BIRCH REDUCTION OF PYRROLES

Abstract Non-alkylated 3,4-dehydroprolines are obtained by diastereoselective protonation after Birch reduction of N-Boc-pyrrole carboxylic amides. Based on quantum chemical calculations the mechanism of asymmetric protonation is discussed.

Eine neue Methode zur Darstellung α-chlorsubstituierter Zimtsäureester

Abstract α-Chlorocinnamates can be easily prepared by the reaction of glycidic esters with in situ prepared chloromethyleneiminium salts.

Eine einfache methode zur herstellung von acceptorsubstituierten α-chlormethylenphosphoranen

Zusammenfassung α-Chlorophosphoranes can be easily prepared by the reaction of the corresponding phosphonium salts with bleaching powder in protic solvents.