The aim of the research work carried out in this book is to synthesize new chiral N-phenylsulfonyl-α-aminohydrazides from naturally occurring amino acids. The present work can be divided into three parts: - The first part is devoted to the synthesis of a series of chiral N-phenylsulfonyl-α-amino acids from naturally occurring α-amino acids.- The second part describes the synthesis of chiral N-phenylsulfonyl-α-aminoesters by esterification of the N-phenylsulfonyl amino acids obtained previously.- The third part deals with the synthesis of chiral N-phenylsulfonyl-α-aminohydrazides by condensation of the α-aminoesters obtained with hydrazine.