Base-catalyzed condensation of 10-methylenecamphor with diethyl oxalate gav
e the corresponding (Z)-3-ethoxycarbonyl(hydroxy)methylene derivative which
was converted into methyl ether and acetate. The Z-methyl ether undergoes
isomerization into the E-methyl ether on treatment with N-bromosuccinimide
in the presence of radical initiator [azobis(isobutyrodinitrile)]. (Z)-3-Et
hoxycarbonyl(hydroxy)methylene-10-methylenecamphor smoothly reacts with N-b
romosuccinimide to afford stereoisomeric 3-bromo derivatives.