ε-Amino acids based on bicyclic skeleton: bicyclo[3.3.0]octane-5-amino-1-carboxylic acids

Tsc-protected ε-amino acids, bicyclo[3.3.0]octane-5-amino-1-carboxylic acids (1), are prepared from 4,4-diethylcarboxylic bicyclo[3.3.0]oct-2-enone (3), which is available in bulk from 2 through the catalytic Pauson-Khand reaction.