Whitehurst WG, Gaunt MJ. Synthesis and Reactivity of Stable Alkyl-Pd(IV) Complexes Relevant to Monodentate
N-Directed C(sp
3)-H Functionalization Processes.
J Am Chem Soc 2020;
142:14169-14177. [PMID:
32697079 DOI:
10.1021/jacs.0c04732]
[Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Alkyl-Pd(IV) complexes are frequently invoked in the proposed mechanisms of Pd-catalyzed C(sp3)-H functionalization reactions, though few examples of Pd(IV) complexes containing cyclopalladated substrates have been isolated due to the instability of the high-valent Pd(IV) center. Herein, we report the synthesis of stable and isolable OCO pincer-supported alkyl-Pd(IV) complexes containing cyclopalladated alkylamine and oxime frameworks, which represent the first examples of alkyl-Pd(IV) complexes derived from the oxidation of cyclopalladated monodentate N-donor substrates. The aminoalkyl-Pd(IV) complexes reacted efficiently with O- and N-nucleophiles to afford γ-functionalized alkylamine products. A mechanistic study of the nucleophile-mediated reductive elimination was conducted using an oxime-derived Pd(IV) complex, which revealed the intermediacy of a previously unexplored anionic Pd(IV) species.
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