Abstract The phosphonium salt from tributylphosphine and 2, 6-di (4-methoxyphenyl) pyrylium perchlorate (3) reacted with diisopropylethylamine in acetonitrile to give 2, 2′, 6, 6′-tetra (4-methoxyphenyl)-Δ 4.4′-bi-4H-pyran in quantitative yield. The reaction of 3 and other 4H-pyrylium salts with tertiary amines gave 4H-pyrans.
