Practical synthesis of trans-tert-butyl-2-aminocyclopentylcarbamate and resolution of enantiomers

Optically active trans-tert-butyl-2-aminocyclopentylcarbamate (1) has potential utility as a scaffold for chiral ligands and as a modified backbone unit for peptide nucleic acids (PNAs). We have developed a short and practical synthesis of 1 via aziridine opening of tosyl-activated cyclopentene aziridine 2 and optical resolution of racemic 1 with 10-camphorsulfonic acid (CSA). The route provides ready access to multigram quantities of both enantiomers without the need for chromatography.