Beta-hydroxy-¦Ã-amino Acid Asymmetric Synthesis And Pyrrolidone N-¦Á-carbanion Synthon

β -Hydroxy-y-amino acid skeletons are found in many natural bioactive compounds, and have important significance in pharmaicological, biochemical as well as clinical studies. As a result, their syntheses have attracted much attention.One aim of this thesis is to finish a versatile asymmetric synthetic method to various substituted R alkyl y-alkyl- P -hydroxy-y-amino acids on which our laboratory has been worked.First, starting from (/?) -malic acid, compound II was prepared as an essential component of Hapalosin I, which has a high multidrug-resistance reversal assisting anticancer activity. Besides, starting from (5) -malic acid, compound III was achieved, which is an enantiomer analog of compound II. by replacing II with III in the configuration, Hapalosin I can exhibit a good assisting anticancer activity.Second, the key intermediate V for antibiotic Preussin IV has been synthesized , which constituted a formal asymmetric synthesis of Presussin IV. In this work, PCC oxidation and NaBH4 stereoselectivity reduction of VI afforded V in 22.7% yield.Third, we have studied stereochemistry in intermediate X for Isostatine VII, a segment of antiviral cyclodepsipeptide. Starting from (5) -malic acid, via a reductive alkylation procedure (Grignard reagent addition then reduced by Et3SiH in the Presence of BF3 ?OEt2), a mixture of two inseparable diastereoisomers X was achieved in a ratio 63: 37. The chirl center configurations of the major are (45, 5Jf, 65)-, which can lead to Isostatine VII.The other aim of this thesis is to study the new chiron XI. Conditons were established for the formation of Chiron XI, as well as for N-a. alkylation of XI. In this work, alkylation shows a high diastereoselectivity (approximately 100%). Thus, the present work would provide a concise access to Castanospermine XII, which shows an interesting anticancer activity. An intermediate XIII for Preussin IV has also been synthesized via this procedure.