Rhodium-catalysed syn-carboamination of alkenes via a transient directing group

Chemical methods for adding carbon-based or nitrogen-based functional groups to alkenes are well established, but strategies for adding both to the same double bond have limitations; here, a method for the carboamination of alkenes at the same double bond is described. Difunctionalization reactions of alkenes are particularly important reactions, as they can be used to access highly complex molecular architectures. Stereoselective oxidation reactions — including dihydroxylation, aminohydroxylation and halogenation reactions — are well-established methods for functionalizing alkenes. However, the intermolecular incorporation of both carbon- and nitrogen-based functionalities stereoselectively across an alkene has not been reported. In this manuscript, Tiffany Piou and Tomislav Rovis describe the Rh(III)-catalysed syn-carboamination of alkenes initiated by a C–H activation event that uses enoxyphthalimides as the source of the carbon and nitrogen functionalities. The reaction methodology allows for the stereospecific formation of one C–C and one C–N bond across an alkene in a fully intermolecular manner. Alkenes are the most ubiquitous prochiral functional groups—those that can be converted from achiral to chiral in a single step—that are accessible to synthetic chemists. For this reason, difunctionalization reactions of alkenes (whereby two functional groups are added to the same double bond) are particularly important, as they can be used to produce highly complex molecular architectures1,2. Stereoselective oxidation reactions, including dihydroxylation, aminohydroxylation and halogenation3,4,5,6, are well established methods for functionalizing alkenes. However, the intermolecular incorporation of both carbon- and nitrogen-based functionalities stereoselectively across an alkene has not been reported. Here we describe the rhodium-catalysed carboamination of alkenes at the same (syn) face of a double bond, initiated by a carbon–hydrogen activation event that uses enoxyphthalimides as the source of both the carbon and the nitrogen functionalities. The reaction methodology allows for the intermolecular, stereospecific formation of one carbon–carbon and one carbon–nitrogen bond across an alkene, which is, to our knowledge, unprecedented. The reaction design involves the in situ generation of a bidentate directing group and the use of a new cyclopentadienyl ligand to control the reactivity of rhodium. The results provide a new way of synthesizing functionalized alkenes, and should lead to the convergent and stereoselective assembly of amine-containing acyclic molecules.