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Analytically pure novel dibenzylsulfanes 2a,b were synthesized by established reactions. Their oxidation by hydrogen peroxide resulted in the formation of the corresponding sulfones 3a,b, which were isolated in high yields. Analogously, the new bis-sulfone 7 was prepared starting from bis-bromo derivative 4 via bis-sulfane 6. The sulfones obtained reacted readily with bis-imidoylchlorides 8, yielding highly substituted dihydrothiophene-S,S-dioxides of type 9 and 10. Due to their vicinal amino-imino substructures, these cyclic sulfones proved to be excellent chelating ligands, exemplified by the preparation of the palladium complex 11. [ABSTRACT FROM AUTHOR]

The reaction of bis -imidoylchlorides derived from oxalic acid with dibenzyl sulfones, afforded novel highly substituted thiophene-1,1-dioxide derivatives. [ABSTRACT FROM AUTHOR]

The first Barton-Kellogg olefination employing thioamides or thioureas as substrates is reported. Starting from the conjugated dithioxo compounds 1 and diazocompounds 2 we substituted the C&dbnd;S groups by ester substructures mono- (type 3 ) and obtained the disubstituted products 4 . Using the same procedure, the tricyclic thiourea 5 was converted into a new ketene aminal 6 . Intermediates such as primary cycloadducts or three-membered ring-contraction products could not be isolated for any reactions studied here. [ABSTRACT FROM AUTHOR]