Facile triphenylphosphine deoxygenation of benzofuran dioxetanes, their epoxides and valence-isomeric quinone methides

Article abstract of DOI:10.1016/0040-4039(94)88076-X

The triphenylphosphine deoxygenation of 2,3-dimethylbenzofuran, 2,3-dimethylindole- and 2,3-dimethylindene dioxetanes 2 leads to the respective epoxides 4 through the intermediary phospholanes 3, of which the indene and indole derivatives 3d, e were detected by low-temperature NMR spectroscopy; with excess PH₃P the benzofuran dioxetane 2a affords the benzofuran 1a, a novel process in which the resulting benzofuran epoxide 4a is in situ deoxygenated.