(1R,2R,3R,4S)-3-[Benzyl-((S)-1-benzylcarbamoyl-propyl)-amino]-7-oxa-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid methyl ester

(E)-3-[Benzyl-((S)-1-benzylcarbamoyl-propyl)-amino]-acrylic acid methyl ester

(E)-3-[Benzyl-((S)-1-benzylcarbamoyl-2-phenyl-ethyl)-amino]-acrylic acid methyl ester

(E)-3-{Benzyl-[(S)-benzylcarbamoyl-(3-methoxy-phenyl)-methyl]-amino}-acrylic acid methyl ester

(E)-3-{Benzyl-[(S)-benzylcarbamoyl-(4-chloro-phenyl)-methyl]-amino}-acrylic acid methyl ester