The addition of butyllithium at-100" C to w-bromoalkyl ethers of o-bromophenol (and its congeners) led to preferential exchange of the aryl bromine at position 2. The resulting organolithium reagents, under suitable conditions, cyclized to afford 2, 3- dihydrobenzofurans (6), 3, 4-dihydro-Wl-benzopyrans (13), or 2, 3, 4, 5-tetrahydro-1- benzoxepins (16) in good yields, but less satisfactory reaulta were obtained with the ...
