SYNTHESIS OF ,5S)-1-AMINO-3-(HYDROXYMETHYL)BICYCLO[3.1.0]HEXANE AS A PRECURSOR FOR THE SYNTHESIS OF CARBOCYCLIC NUCLEOSIDES

The stereocontrolled synthesis has been achieved of a 1,5-methano-1-am ino-5-(hydroxymethyl)cyclopentane, a potential component for carbocycl ic nucleosides. Stereocontrol was manifest by converting (R)-2-((benzy loxy)ethyl)oxirane specifically to (2S,3S)-2-amino-2,3-methanoadipate through a series of lactones. This aminocyclopropanecarboxylate was th en cyclized to the corresponding cyclopentanone ester. Reduction of th e ketone, elimination, and hydrogenation of the double bond led primar ily to the cyclopentane with the amino and ester groups trans (9/1). E nolization followed by an ammonium chloride quench then inverted this to a mixture in which the cis isomer was dominant(4/1). Simple functio nal group manipulation then gave the target 5S)-1-amino-3-(hydroxymeth yl)bicyclo[3.1.0]hexane.