127311-92-6 5-endo-(Cyanomethyl)-7-oxabicyclo(2.2.1)heptane-2-exo,3-exo-dicarboxylic acid 5-endo-(Cyanomethyl)endothall 7-Oxabicyclo(2.2.1)heptane-2,3-dicarboxylic acid, 5-(cyanomethyl)-, (2-exo,3-exo,5-endo)-