New synthesis of 2-aryl-3-substituted benzo[b]furans from benzyl 2-halophenyl ethers.

Treatment of benzyl 2-halophenyl ethers with 3 equiv of t-BuLi results in Li−halogen exchange and lithiation at benzylic methylene simultaneously. These dianions do not undergo Wittig rearrangement and can be trapped with electrophiles. Their reactions with carboxylic esters afford the corresponding 2-aryl-3-hydroxy-2,3-dihydrobenzo[b]furans as a mixture of diastereoisomers. Subsequent acid-catalyzed or mediated dehydration gives moderate to good overall yield of a variety of 2-aryl-3-substituted benzo[b]furans.