Direct C-H Cyanation by ICN Formed In Situ : Nannozinone B.

A novel method for C-H cyanation of different pyrans, pyrroles, indoles, and acyclic nucleophilic double bonds using TMSCN, NIS, and Zn(OTf) 2 as a catalyst is described. The transformation is conducted under mild conditions tolerating a variety of functional groups. Zn(OTf) 2 is likely to serve a dual catalytic role as an activator for TMSCN and for the cyanogen iodide generated in situ . Optimization, the substrate scope, and mechanistic observations are reported. Furthermore, this method is applied in the first total synthesis of the natural product nannozinone B.