A cyanoborohydride-promoted radical cyclization methodology has been developed to access α-chlorolactams in a simple and efficient way, using NaBH3CN and trichloroacetamides easily available from allylic and homoallylic secondary amines. This methodology allowed the synthesis of a library of αchlorolactams (mono and bicyclic), which were tested for herbicidal activity, trans-3-chloro-4-methyl-1-(3-trifluoromethyl)phenyl-2-pyrrolidinone being the most active.