(1α,2β,4β,6α)-3,8-dioxatricyclo<4.2.1.02,4>nonan-7-one

Methyl (1R,2R,3S,4S,5R)-2,3-O,O-isopropylidene-2,3-dihydroxy-7-oxabicyclo<2.2.1>heptane-5-carboxylate

methyl (1R,5R,6S)-5-hydroxy-7-oxabicyclo[4.1.0]hept-2-ene-3-carboxylate