Martínez ÁM, Echavarren J, Alonso I, Rodríguez N, Gómez Arrayás R, Carretero JC. Rh
I/Rh
III catalyst-controlled divergent aryl/heteroaryl C-H bond functionalization of picolinamides with alkynes.
Chem Sci 2015;
6:5802-5814. [PMID:
29861907 PMCID:
PMC5950197 DOI:
10.1039/c5sc01885d]
[Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 06/27/2015] [Indexed: 11/21/2022] Open
Abstract
The ability to establish switchable site-selectivity through catalyst control in the direct functionalization of molecules that contain distinct C-H bonds remains a demanding challenge that would enable the construction of diverse scaffolds from the same starting materials. Herein we describe the realization of this goal, namely a divergent heteroaryl/aryl C-H functionalization of aromatic picolinamide derivatives, targeting two distinct C-H sites, either at the pyridine ring or at the arene unit, to afford isoquinoline or ortho-olefinated benzylamine (or phenethylamine) derivatives. This complementary reactivity has been achieved on the basis of a RhIII/RhI switch in the catalyst, resulting in different mechanistic outcomes. Notably, a series of experimental and DFT mechanistic studies revealed important insights about the mechanism of the reaction and reasons behind the divergent regiochemical outcome.
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