THERMAL YLIDE REARRANGEMENT AND BASE CATALYZED METHYLSULFONIO GROUP MIGRATION OF METHYLSULFONIUM 1-(2,6-DIPHENYL AND 2,3,5,6-TETRAPHENYL-4H-PYRAN-4-YL)-2-OXO-2-PHENYLETHYLIDES

Article abstract of DOI:10.1246/cl.1981.1535

Thermolyses of dimethylsulfonium 1-(2,6-diphenyl and 2,3,5,6-tetraphenyl-4H-pyran-4-yl)-2-oxo-2-phenylethylides (1 and 3) caused a novel <1,3> ylide rearrangement to give dimethylsulfonium 1-benzoyl-6-oxo-2,6-diphenyl and 2,3,5,6-tetraphenyl-2,4-hexadienylides (6 and 7) respectively.The formations of oxy-thio-acetal derivatives (11 and 12) of 4-pyranylidene from 3 and its methylphenylsulfonium analogue (4) by base treatment are also reported.