(E)-(4R,5S)-4-Benzyloxy-5-hydroxy-hex-2-enoic acid (S)-2-[(E)-(1S,2R)-2-benzyloxy-1-methyl-4-(2,2,2-trichloro-ethoxycarbonyl)-but-3-enyloxycarbonyl]-1-methyl-ethyl ester

(E)-(4R,5S)-4-Benzyloxy-5-hydroxy-hex-2-enoic acid (E)-(1S,2R)-2-benzyloxy-1-methyl-4-[(S)-1-methyl-2-(2,2,2-trichloro-ethoxycarbonyl)-ethoxycarbonyl]-but-3-enyl ester

(E)-(4R,5S)-4-Benzyloxy-5-(tert-butyl-dimethyl-silanyloxy)-hex-2-enoic acid (E)-(1S,2R)-2-benzyloxy-1-methyl-4-[(S)-1-methyl-2-(2,2,2-trichloro-ethoxycarbonyl)-ethoxycarbonyl]-but-3-enyl ester