RhodiumA Regioselective Direct C-2 Alkenylation of Indoles Assisted by the Removable N-(2-Pyrimidyl) Group

The C-2-alkenylindole unit is a key com- ponent of numerous natural products and pharma- cophores. However, the intermolecular direct con- struction of the core structural motif remains chal- lenging in organic synthesis. Here we report a new, efficient, and versatile methodology for the synthe- sis of C-2-alkenylindoles through rhodiumA lyzed direct CH functionalization of indoles with acrylates under air by employing a metal-directing group strategy. This strategy gives a rare selectivity for the alkenylation N-(2-pyrimidyl)indoles at the C-2 position and provides the functionalized C-2- alkenylindoles under mild conditions with broad substrate tolerance. An expansion of the methodol- ogy has also been demonstrated to, for example, the direct alkenylation of pyrrole and facile depro- tection of the pyrimidyl group. All the results sug- gest that this methodology could be served as a highly attractive alternative for the direct con- struction of biologically important C-2-alkenylin- doles.