5 research outputs found
Intermediacy of NiāNi Species in sp<sup>2</sup> CāO Bond Cleavage of Aryl Esters: Relevance in Catalytic CāSi Bond Formation
Monodentate phosphine
ligands are frequently employed in the Ni-catalyzed
CāO functionalization of aryl esters. However, the extensive
body of preparative work on such reactions contrasts with the lack
of information concerning the structure and reactivity of the relevant
nickel intermediates. In fact, experimental evidence for a seemingly
trivial oxidative addition into the CāO bond of aryl esters
with monodentate phosphines and low-valent nickel complexes still
remains elusive. Herein, we report a combined experimental and theoretical
study on the Ni(0)/PCy<sub>3</sub>-catalyzed silylation of aryl pivalates
with CuF<sub>2</sub>/CsF additives that reveals the involvement of
unorthodox dinickel oxidative addition complexes in CāO bond
cleavage and their relevance in CāSi bond formation. We have
obtained a mechanistic picture that clarifies the role of the additives
and demonstrates that dinickel complexes act as reservoirs of the
propagating monomeric nickel complexes by disproportionation. We believe
this study will serve as a useful entry point to unravelling the mechanistic
underpinnings of other related Ni-catalyzed CāO functionalization
reactions employing monodentate phosphines
Intermediacy of NiāNi Species in sp<sup>2</sup> CāO Bond Cleavage of Aryl Esters: Relevance in Catalytic CāSi Bond Formation
Monodentate phosphine
ligands are frequently employed in the Ni-catalyzed
CāO functionalization of aryl esters. However, the extensive
body of preparative work on such reactions contrasts with the lack
of information concerning the structure and reactivity of the relevant
nickel intermediates. In fact, experimental evidence for a seemingly
trivial oxidative addition into the CāO bond of aryl esters
with monodentate phosphines and low-valent nickel complexes still
remains elusive. Herein, we report a combined experimental and theoretical
study on the Ni(0)/PCy<sub>3</sub>-catalyzed silylation of aryl pivalates
with CuF<sub>2</sub>/CsF additives that reveals the involvement of
unorthodox dinickel oxidative addition complexes in CāO bond
cleavage and their relevance in CāSi bond formation. We have
obtained a mechanistic picture that clarifies the role of the additives
and demonstrates that dinickel complexes act as reservoirs of the
propagating monomeric nickel complexes by disproportionation. We believe
this study will serve as a useful entry point to unravelling the mechanistic
underpinnings of other related Ni-catalyzed CāO functionalization
reactions employing monodentate phosphines
Intermediacy of NiāNi Species in sp<sup>2</sup> CāO Bond Cleavage of Aryl Esters: Relevance in Catalytic CāSi Bond Formation
Monodentate phosphine
ligands are frequently employed in the Ni-catalyzed
CāO functionalization of aryl esters. However, the extensive
body of preparative work on such reactions contrasts with the lack
of information concerning the structure and reactivity of the relevant
nickel intermediates. In fact, experimental evidence for a seemingly
trivial oxidative addition into the CāO bond of aryl esters
with monodentate phosphines and low-valent nickel complexes still
remains elusive. Herein, we report a combined experimental and theoretical
study on the Ni(0)/PCy<sub>3</sub>-catalyzed silylation of aryl pivalates
with CuF<sub>2</sub>/CsF additives that reveals the involvement of
unorthodox dinickel oxidative addition complexes in CāO bond
cleavage and their relevance in CāSi bond formation. We have
obtained a mechanistic picture that clarifies the role of the additives
and demonstrates that dinickel complexes act as reservoirs of the
propagating monomeric nickel complexes by disproportionation. We believe
this study will serve as a useful entry point to unravelling the mechanistic
underpinnings of other related Ni-catalyzed CāO functionalization
reactions employing monodentate phosphines
Intermediacy of NiāNi Species in sp<sup>2</sup> CāO Bond Cleavage of Aryl Esters: Relevance in Catalytic CāSi Bond Formation
Monodentate phosphine
ligands are frequently employed in the Ni-catalyzed
CāO functionalization of aryl esters. However, the extensive
body of preparative work on such reactions contrasts with the lack
of information concerning the structure and reactivity of the relevant
nickel intermediates. In fact, experimental evidence for a seemingly
trivial oxidative addition into the CāO bond of aryl esters
with monodentate phosphines and low-valent nickel complexes still
remains elusive. Herein, we report a combined experimental and theoretical
study on the Ni(0)/PCy<sub>3</sub>-catalyzed silylation of aryl pivalates
with CuF<sub>2</sub>/CsF additives that reveals the involvement of
unorthodox dinickel oxidative addition complexes in CāO bond
cleavage and their relevance in CāSi bond formation. We have
obtained a mechanistic picture that clarifies the role of the additives
and demonstrates that dinickel complexes act as reservoirs of the
propagating monomeric nickel complexes by disproportionation. We believe
this study will serve as a useful entry point to unravelling the mechanistic
underpinnings of other related Ni-catalyzed CāO functionalization
reactions employing monodentate phosphines
Iridium-Catalyzed, Substrate-Directed CāH Borylation Reactions of Benzylic Amines
The iridium-catalyzed arene CāH borylation reaction of benzylic amines has been developed, which inverts the typical steric-controlled product distribution to provide <i>ortho</i>-substituted boronate esters. Picolylamine was found to be an ideal ligand to replace 4,4ā²-di-<i>tert</i>-butylbipyridine to induce the directing effect. Preliminary experiments are consistent with a mechanism involving dissociation of one amine of the hemilabile diamine ligand