Raney-Co mediated reductive cyclization of an α,β-unsaturated nitrile

An expedient, five step synthesis of caprolactam 1 is reported starting, from natural L-homoserine. The key step is a chemoselective reductive cyclization of alpha,beta-unsaturated nitrile 10 mediated by Raney-Co type metals. This hydrogenation is extensively investigated in order to account for the observed product distribution and yields.