REACTIONS OF TRANSITION-METAL ETA(1)-PROPARGYL AND ETA(1)-ALLENYL COMPLEXES WITH SULFUR-DIOXIDE AND TRANSITION-METAL-CARBON BOND-CLEAVING REACTIONS OF THE CYCLOADDUCTS WHICH YIELD CYCLIC SULFENATE ESTERS

The preparation of several cyclopentadienyliron dicarbonyl eta(1)-2-al kynyl and eta(1)-allenyl complexes is reported. The 3 + 2 cycloadditio n reactions of these complexes with sulfur dioxide yielded regioisomer ic transition-metal-substituted 1,2-oxathiolen-1-yl oxides (sulfenate esters). One of the eta(1)-allenyl complex SO2 cycloadducts has been c haracterized by X-ray crystallography. The transition metal can subseq uently be cleaved from the sulfenate ester containing complexes under oxidative and nonoxidative reaction conditions to produce a variety of new sulfur-containing heterocycles.