A Divergent Strategy for Site-Selective Radical Disulfuration of Carboxylic Acids with Trisulfide-1,1-dioxides
Derek Pratt reports on the radical disulfuration of carboxylic acids with trisulfide-1,1-dioxides.
According to Professor Derek Pratt from the University of Ottawa (Canada), making symmetric disulfides bonds is relatively easy. He said that “anyone that has worked with thiols knows that this often happens inadvertently, simply upon exposure to air” and added that “the preparation of unsymmetric di-sulfides is another matter. A thiol is generally first activated to reaction with another by converting it into an electrophile – the most common example being a symmetric disulfide. Thus, one thiol reacts with the symmetric disulfide derived from a second thiol to create an unsymmetric disulfide. This so-called ‘disulfide exchange’ reaction is ubiquitous in biology; but controlling these reactions in a synthetic context can be tricky since exchange reactions are generally equilibria and can require large excesses of thiol to push the reaction forward.” The efforts of the Pratt group to develop a new approach to unsymmetric disulfides were derived from largely unrelated work to understand how allicin, the thiosulfinate responsible for the characteristic odor of garlic, reacted with radicals as an antioxidant.