Preparation of substituted transition-metal (η1-propargyl complexes and their [3+2] cycloaddition reactions with sulfur dioxide and disulfur monoxide. Transition-metal–carbon bond cleaving reactions of the cycloadducts which yield oxathiolene oxides and d

The preparations of several new cyclopentadienyl iron dicarbonyl η1-2-alkynyl complexes are reported. Their [3+2] cycloaddition reactions with sulfur dioxide and disulfur monoxide yielded transition-metal substituted 1,2-oxathiolene-2-oxides and 1,2-dithiolene-1-oxides, respectively. The transition-metal was cleaved from the oxathiolene-oxide and dithiolene-oxide containing complexes to produce new sulfur heterocycles.