We report both an intermolecular
C–H amination of arenes
to access N-methylanilines and an intramolecular
variant for the synthesis of tetrahydroquinolines. A newly developed,
highly electrophilic aminating reagent was key for the direct synthesis
of unprotected N-methylanilines from simple arenes.
The reactions display a broad functional group tolerance and employ
catalytic amounts of a benign iron salt under mild reaction conditions.
Electrophilic aminating reagents have seen a renaissance in recent years as effective nitrogen sources for the synthesis of unprotected amino functionalities.
Classical metalation reactions such as the metal-halogen exchange are powerful tools to construct chemical bonds between two molecules. An analogous metal-carbon exchange strategy would provide a new entry into the direct structural remodeling of core carbon frameworks, yet its development has remained highly challenging. Here we introduce a skeletal metalation strategy that enables lactams, a highly prevalent motif in bioactive molecules, to be readily converted into well-defined, synthetically useful organonickel reagents. The reaction features a selective activation of unstrained CN bonds mediated by an easily prepared Ni(0) reagent, followed by CO deinsertion and dissociation under mild room temperature conditions in a formal carbonyl-to-nickel exchange process. The underlying principles of this unique reactivity was rationalized by organometallic and computational studies. The skeletal metalation was further applied to a direct CO excision reaction and a carbon isotope exchange reaction of lactams, underscoring the synthetic potential of metal-carbon exchange logic for skeletal modifications of complex molecules.
Site-selective late-stage functionalizations of a pyrano[3,2-a]carbazole core related to the murrayamine natural products is reported. Specifically, selective C3 and C6 bromination has been achieved as well as C8 borylation. These functionalizations set the stage for access to a variety of natural products as well as their derivatives.Note pubs.acs.org/joc
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