Preparation of 8-amido-2-dimethylamino-1,2,3,4-tetrahydro-2-dibenzofurans and several fluorinated derivatives via [3,3]-sigmatropic rearrangement of O-aryloximes

Methodology to prepare 8-amido-2-amino-1,2,3,4-tetrahydro-2-dibenzofurans, analogues with a fluorine substituent incorporated in the 6-, 7-, and 9-positions, and a difluorinated analogue with fluorines in the 6- and 9-positions is described. The tetrahydrodibenzofuran ring systems are prepared by acid-catalyzed [3,3]-sigmatropic rearrangement of O-aryloximes. Regioselective reactions to prepare the requisite O-aryloxime intermediates from commercially available fluorobenzene derivatives are discussed.