Process of preparation of tetrafluoro 2,3-dihydrobenzofurans
AssigneeFMC Corporation
InventorsDavid E. Seelye, Ernest L. Plummer
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Abstract
Tetrafluorobenzofurans of the formula ##STR1## are prepared by contacting, at elevated temperature in an aprotic solvent, an ether of the formula ##STR2## with a catalytic mixture of metallic cooper and a polydentate or other ligand, wherein R.sup.1 is hydrogen, nitro, amino, phthalimido or acetylimido, R.sup.2 is at least one of hydrogen, halo, cyano, alkyl, hydroxy, alkoxy, acyl, acyloxy, alkoxycarbonyl, alkoxycarbonylalkyl, phenyl, phenyloxy, trifluoromethyl or dialkylamino. The products are intermediates in the preparation of pyrazoline insecticides.
Claims11
A cyclization process for preparing benzofurans of the formula:
- ##STR9## which comprises contacting, at elevated temperature in an aprotic solvent, an ether of the formula:
- ##STR10## with a catalyst comprising a mixture of metallic copper and a ligand therefor, and separating the resulting benzofuran, wherein R.sup.1 is hydrogen, nitro, amino, phthalimido or acetamido, R.sup.2 is hydrogen or a substituent which is non-interfering in the cyclization, m is 0-3, and X.sup.1 and X.sup.2 independently are chloro, bromo or iodo.
Dependencies are inferred from the claim text.