The synthesis of epoxides 2 by the reaction of the chloro-and methyl-substituted 2, 3- dimethylbenzofurans 1 with dimethyldioxirane at low temperature is reported. These labile epox-ides were spectroscopically characterized (lH and 13C NMR) at subambient temperatures. Epoxidation of benzofuran lc af-fords a 31: 69 mixture of epoxide 2c and quinone methide 3c, the latter presumably being produced by valence isomerization of the ...