W (CO) 5 (NCMe)(1) has been found to transform vinylthiirane and a series of methyl- substituted vinylthiiranes into a series of 3, 6-dihydro-1, 2-dithiin compounds. Two equivalents of the vinylthiirane are required, and 1 equiv of a butadiene is formed by the transfer of its sulfur atom to the second vinythiirane, which is then transformed into the dihydrodithiin. The formation of 3, 6-dihydro-1, 2-dithiin (9) proceeds at 15 turnovers/h at ...
