화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.142, No.33, 14169-14177, 2020
Synthesis and Reactivity of Stable Alkyl-Pd(IV) Complexes Relevant to Monodentate N-Directed C(sp(3))-H Functionalization Processes
Alkyl-Pd(IV) complexes are frequently invoked in the proposed mechanisms of Pd-catalyzed C(sp(3))-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 gamma-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.