ethyl 4(R)-<(1R)-3(S),4,8(R)-trimethyl-6-oxo-2,9-dioxabicyclo-<3.3.1>non-4(Z)-en-1-yl>-2-methylpent-2(E)-enoate

(3S,3aS,6S,7aS)-6-Benzyloxy-3-methyl-5-methylene-hexahydro-furo[3,2-b]pyran-2-one