ChemInform Abstract: Synthesis and Thermal Reactions of New Cyclic Sulfur Ylides Possessing 10π Electrons, 8-Alkyl-1,3-diphenyl-2H-dibenzo(b,f)cyclopenta(d)thiepinio-2-ides.

ChemInform Abstract

The cyclopentadienodibenzothiepin (II), prepared by reduction of the ketone (I), is alkylated with the iodides (III) in the presence of silver chlorate to form the thiaazulenium salts (IV). These are deprotonated with sodium hydride, producing the S-ylides (V) which undergo thermal rearrangement reactions: (Va) yields the 1,4-rearranged compound (II). (Vb) and (Vc) produce (VIb) and (VIc) and the1,2-rearranged derivatives (VII). Methylation of (II) gives (VIa) and (IX) or (X).