Study On The Synthesis Of β,γ-Unsaturated-α-amino Acids

β,γ-Unsaturated-α-amino acids are important motifs present in many biologically active natural products and characteristic of direct attachment of C=C double bond on a-position of amino group. These compounds can be used as pharmaceutics such as enzyme inhibitors and agricultural chemicalsantibiotics. So it is of important value to study these compounds.In this dissertation, the synthesis and characterization of (±)-2-amino-3-methylenepentanoic acid Hydrochloride, (±)-2-amino-4-methoxy-3-butenoic acid (MVG) were studied.Two strategies have been developed toward the synthesis of (±)-2-amino-3-methylenepentanoic acid from L-serine. The Weinreb’s amide route afforded the product with an overall yield of 17% via 7 steps including acelation, cyclization, Grignard reaction. The Grignard reaction was emphasized studied and the reaction conditions were optimized. Moreover, the Garner’s aldehyde route was achieved via 10 steps in 39% overall yield including reduction, oxidation, Grignard reaction, Wittig reaction, Jones oxidation. The reaction conditions of oxidation and Wittig reaction were optimized.In addition, the effort to synthesize MVG was tried through three routes and obtained some precusors. The Garner’s aldehyde route based on L-serine and completed 7 steps including protection, cyclization, reduction, oxidation and Witiig reaction. This route was stopped at the oxidation of hydroxyl to carboxyl might due to the stable five-membered cyclic intramolecular hydrogen bond. The pyrolytic elimination route completed 5 steps using L-methionine as the raw material. The ortho-ester route from L-serine completed 6 steps including protection, esterification and cyclization.In conclusion, (±)-2-amino-3-methylenepentanoic acid hydrochloride was synthesized through the Weinreb’s amide route and Garner’s aldehyde route for the first time, and the both routes are universally promising for the synthesis of otherβ,γ-unsaturated-α-amino acids. Three routes to synthetise MVG were tried and gave some valuable results and intermediates.