((2R,3S,4aR,5aS,10aS,11R,11aR)-11-Benzyloxy-3-methoxymethoxy-2,3,4,4a,5a,6,9,10a,11,11a-decahydro-1,5,10-trioxa-cyclohepta[b]naphthalen-2-yl)-acetic acid ethyl ester

(E)-3-((2R,3R,4R,4aS,9aS)-4-Benzyloxy-2-[1,3]dithian-2-ylmethyl-3,4,4a,6,9,9a-hexahydro-2H-1,5-dioxa-benzocyclohepten-3-yloxy)-acrylic acid ethyl ester