An efficient sequence for the preparation of small secondary amine hydrochloride salts for focused library generation without need for distillation or chromatographic purification

Collections of small secondary amines for compound library generation can be efficiently prepared by amide reduction using BH3–THF or Red-Al followed by brief methanolysis, trapping with di-tert-butyl dicarbonate, and deprotection with 4 M HCl in dioxane. The sequence requires no chromatography or distillation and provides multi-gram quantities of pure HCl salts in a short time.