A Novel One-Pot Synthesis of Different Derivatives of Tetraarylterephthal­aldehyde via a Multiple Aryne Sequence

The synthesis of a novel series of tetraarylterephthalaldehyde derivatives in an one-pot reaction is described. In this methodology 1,2,4,5-tetrachloro-3,6-diiodobenzene is treated with various aryl Grignard reagents (excess) in tetrahydrofuran to give tetraarylbenzene-1,4-diylbis(magnesium bromides). After reaction of this product with ethyl formate and aqueous quench, tetraarylterephthalaldehydes are isolated in 33-80% yields. A mechanism involving organometallic aryne intermediates is proposed.