Reaction of hydrogen fluoride in pyridine solution with cis-cyano-2-and cis-amido-2-aziridines. Preparation of β-fluoro-α-amino acids and esters by means of acidic hydrolysis and alcoholysis of β-fluoro-α-amino nitriles and/or β-fluoro-α-amino acid amides

Abstract

The addition of hydrogen fluoride generated from pyridinium poly(hydrogen fluoride)(i.e. Olah's reagent) to some cis-2-cyano- and cis-2-amido-aziridines has been examined.

The reaction led to fluoroamine derivatives which upon acidic hydrolysis and alcoholysis gave 3-fluoro-2-amino acids and esters in good yields.

The addition of hydrogen fluoride is highly regioselective for both substrates. It was found to be stereospecific for cis-2-amidoaziridines since threo-β-fluoro α-amino acid amides were exclusively obtained from the ring-opening with Olah's reagent. cis-2-Cyanoaziridines gave in all cases studied, mixtures (i.e. 57:43) of the threo- and erythro-2-amino-3-fluoronitriles.