N-Heterocyclic Iod(az)olium Salts - Potent Halogen Bond Donors in Organocatalysis

Herein we describe the first systematic investigation of cyclic iodonium salts (iodoliums and iodazoliums) and their performance as XB-donors in a variety of benchmark reactions. It was found that further N-alklyation of the N-heterocycle has a significant influence on their XB-donor capability. These novel dicationic species show a reactivity which is comparable or even better than the best so far described iodine(I) and iodine(III) compounds throughout the investigated reaction set.