Asymmetric Synthesis of (1S,2R)-1-Amino-2-methylcyclopropanephosphonic Acid: A Phosphonic Analogue of (–)-Norcoronamic Acid – Influence of Stereochemistry on Regioselectivity in Sulfoxide–Metal Exchange

Abstract

Asymmetric synthesis of (–)-(1S,2R)-1-amino-2-methylcyclopropanephosphonic acid, a phosphonic analogue of (–)-norcoronamic acid was developed. The presence of the nitrile group as a precursor of the amino moiety, by changing stereoselectivity in the alkylation step, in consequence allowed to avoid 1,2-migration of a phosphoryl group on the cyclopropane ring and to obtain the required cyclopropylphosphonate of the retained structure and configuration.