Abstract Irradiation (λ> 366 nm) of the quinone methides 3, which were formed by valence isomerization of the methyl-, chloro-, and tert-butyl-substituted 2, 3-dimethylbenzofuran epoxides 2, afforded the novel 2H-benzoxetes 4 by photochemical [2+ 2] cycloaddition. These strained and highly labile benzoxetes 4 were spectrally (1 H and 13 C NMR) characterized at subambient temperatures. On prolonged storage (2–3 d) at–20 to–10 C, ...
