(2R,3R,5S,2'S,3'R,5'R)-5,2'-Di(R)-1,4-dioxa-spiro[4.5]dec-2-yl-2,5'-dimethoxy-4'-methyl-tetrahydro-[3,3']bifuranyl-3,4'-diol

1(R)-Methoxycarbonyl-2(R)-formyl-4(S)-hydroxycyclopentane

1(R)-2-Oxo-3(R)-methoxy-4(R)-5(R)-methoxycarbonylbicyclo<2,2,1>-heptane

1(R)-Methoxycarbonyl-2(R)-formyl-4(S)-acetoxycyclopentane