Abstract
Eight thiocumulenes of the type X=S=Y (sulfur dioxide, disulfur monoxide, sulfur diimides, sulfinylamines, thiosulfinylamines, thiocarbonyl ylides, thiocarbonyl imines, and sulfines) were reviewed with respect to the structure, the preparation, and the reactivity (Diels-Alder type reaction, ene-reaction, photolysis, thermolysis, and reactions with nucleophiles, free radicals, carbenes, or nitrenes). Following relationships between the reactivity of the cumulene X=S=Y and the electronegativities (χX, χY) of the ligands (X, Y) were found : (1) the less are the values of χX+χY and |χX-χY|, the more is 1, 3-dipolar nature, rather than dienophilic nature, of the cumulene enhanced. (2) When χX>χY, the larger is the value of χX-χY, the more reactive is the S=Y bond. (3) Large value of χX+χY favors nucleophilic attack on to the central sulfur atom over the terminal atoms (X or Y).
