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.

Highly Asymmetric Cyclopropanation With Two Sulfinyl Auxiliaries as a Way to a Useful Synthetic Intermediate

“…Recently we also investigated asymmetric cyclopropanation utilizing sulfinyl auxiliary, this time using designed by us sulfonium ylide containing a sulfinyl group bonded to the ylidic carbon atom . High facial stereoselectivity observed for cyclopropanation of vinylic phosphonates caused this reaction to serve as a new approach to enantiomerically pure, constrained 1‐aminophosphonic acids …”