Gold(I)-Catalyzed 1,3-O-Transposition Reactions: Ynesulfonamides to Ynamides
The gold-catalyzed 1,3-O-transposition reaction of ynesulfonamides provides a practical synthetic protocol for the synthesis of ynamides under mild conditions. This is the first 1,3-O-transposition example of ynesulfonamides in which a heteroatom is attached to the alkynyl terminal. A plausible mechanism is been proposed on the basis of 18O-labeling and control experiments as well as DFT calculation. By simple treatment, the obtained ynamides can easily be transformed into useful products.