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The title compounds (III) are obtained via a two-step one-pot synthesis involving the construction of the cyclohexanone ring from aromatic aldehydes and β-ketoesters as initial step under mild reaction conditions.

10 Title compounds of type (III) are prepared and tested as inhibitors of phosphodiesterase 4 (PDE4).

Indole 2,3-dienolate derived by deprotonation of 1,2-dimethylindole-3-carboxaldehyde is shown to be useful 1,4-dipole synthon (anionic indolo-2,3-quinodimethane) which undergoes facile cycloaddition with wide range of dienophiles affording substituted carbazoles in highly regiospecific fashion.

The cyclopropanes 2a-h having 4-(bismethylthio)butadienyl moiety as donor group, which are easily obtained by regioselective cyclopropanation of vinylogous ketene dithioacetals 1a-h with oxodimethylsulphonium methylide, undergo facile Lewis acid assisted vinylcyclopropyl rearrangement to afford substituted and spiro cyclopentenes 3a-h in good yields.

Acyclic and cyclic aroyl ketene N,S-acetals undergo regioselective deprotonation-cyclization via dipole stabilized carbanion in the presence of LDA/THF to afford the corresponding 2-(cycloalkylamino)-4-aryl or 3,4-annelated thiophenes in moderate to good yields.