Irradiation of a benzene solution containing 3-cyano-2-methoxypyridine (0.0
2 M) and benzofuran (0.5 M) resulted in the formation of stereo-isomeric 1:
1 adducts, endo and exo-7-cyano-2-methoxy-4-methyl-9-oxa-3-aza-10,11-benzot
ricyclo[6.3.0.0(4,7)]undeca-2,5-diene, accompanied by 5-cyano-2-methoxypyri
dine and a pyridine dimer; the structures of the adducts were established b
y X-ray structural analyses.