Fluorobenzene side chains, effect

Intramolecular substitution for chloride or fluoride is particularly effective. Oxygen heterocycles with fused benzo rings are obtained from Cr(CO>3 complexes of fluorobenzene with an o-(hydroxyalkyl) side chain.39,60 For example, complexation of 3-(2-fluorophenyl)-l -propanol with [Cr(CO>3(pyridine)3] at 25 C in ether (promoted by BF3 Et20) followed by reaction in DMSO with excess potassium f-butoxide for 3 h at 25 C gave the chroman complex (14).60 The yield in the cyclization step was 75% and iodine decomplexation was quantitative (equation 12). Efforts to produce the dihydrobenzofuran under the same... 

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