(2S,5S,1'S,2'S,3'R,8'S,10'S,3''S)-5-(1',2'-epoxy-3'-triisopropylsiloxy-6',8',10'-trimethyl-5'-methylene-undec-6'-enoic acid)-2-(3''-hydroxy-hept-5''-(E)-enyl)-3-methylene-tetrahydrofuran