Steric and electronic limitations for the Dotz benzannulation of aromatic alkynes

As part of an investigation into a new strategy for biaryl synthesis, the Dotz benzannulation of a series of substituted aryl acetylenes was undertaken to deterinine possible steric and electronic effects exerted by the aryl group. In the ortho position it was found that methyl, methoxy, chloro N-amide substituents give moderate to good yields of product. whereas carbonyl derivatives and the nitro group are deleterious. (C) 2002 Published by Elsevier Science Ltd.