6-[(6R,7R,8S)-7-((Z)-4-Carboxy-but-2-enyl)-8-hydroxy-1,4-dithia-spiro[4.4]non-6-yl]-4-oxo-hexanoic acid

((6a'R,7'S,9a'S,Z)-7'-(hydroxymethyl)-5-methyl-3',6',6a',7',9',9a'-hexahydrodispiro[[1,3]dioxane-2,2'-cyclopenta[b]oxocine-8',2''-[1,3]dithiolan]-5-yl)methyl benzoate