Stereoselective synthesis of (1R,2R)-1-amino-2-hydroxycyclobutanecarboxylic acid-serine derivative-, from racemic or optically active 2-benzyloxycyclobutanone

An easy and efficient one-pot reaction from readily available 2-benzyloxycyclobutanone gave, by means of an asymmetric Strecker synthesis, a kinetic or thermodynamic nitrile with good selectivity. After separation, the major trans-amino nitrile underwent basic hydrolysis and hydrogenolysis, followed by acidic hydrolysis, to give optically active (1R,2R)-1-amino-2-hydroxycyclobutanecarboxylic acid, serine derivative. The absolute configuration has been established by X-ray analysis of the corresponding cis-amino nitrile.