Publication
Chlorinated pentadienals and pentadienones (I) gave complex pyrylium salts (II) when warmed with Lewis acids 10-15 hrs. at 40-50 Deg. The compds. thus prepared are given in the table. Decompn; R, R', Anion, point, %Yield; Cl, H, SnCl6-, 1701-1.5 Deg, 87; 27.6; H, H, FeCl4, 155-60 Deg, 13; Cl, Ph, SnCl62-, 177-83 Deg, 40.9; SnCL6-, 176-80 Deg, 17.2; Ph, H, SnCl6-, 118-20 Deg, 60; Ph, Ph, FeCl4-, 219-22 Deg, 52; SbCl6-, 128-33 Deg, 28.9; ClO4, 240 Deg, 20; [on SciFinder (R)]