 The Kröhnke synthesis was used to prepare a family of tetrahydroquinoline-based N, S-type ligands.2-thiophenylacetophenone (36) was reacted with iodine gas and pyridine in quantitative yield to generate acylmethylpyridinium iodide 37.Reaction with a chiral cyclic α, β-unsaturated ketone derived from 2-(+)-carene yielded the desired N, S-type ligand 38.