Treatment of 2-phenoxypropionic acid with polyphosphoric acid gave substituted benzofuran-3-ones (2a-h), which were converted into 2,3,4-trihydrodibenzofuran-3-ones (4a-h) via the compounds 3a-h. Clemmensen reduction of the compounds 4a-h gave the 2,3,4-trihydrodibenzofuranes(5a-h).
Treatment of 2-phenoxypropionic acid with polyphosphoric acid gave substituted benzofuran-3-ones (2a-h), which were converted into 2,3,4-trihydrodibenzofuran-3-ones (4a-h) via the compounds 3a-h. Clemmensen reduction of the compounds 4a-h gave the 2,3,4-trihydrodibenzofuranes(5a-h).