1609175-16-7Relevant academic research and scientific papers
Chromium-Salen Catalyzed Cross-Coupling of Phenols: Mechanism and Origin of the Selectivity
Nieves-Quinones, Yexenia,Paniak, Thomas J.,Lee, Young Eun,Kim, Sun Min,Tcyrulnikov, Sergei,Kozlowski, Marisa C.
supporting information, (2019/07/03)
A highly chemoselective phenol cross-coupling reaction catalyzed by a Cr-salen catalyst was developed. Kinetic studies showed that the oxidation of Cr(III) to Cr(V) is the rate-determining step of the reaction. In addition, experimental stoichiometric analysis showed that a high valent Cr(V) species is the active catalyst for this process. The selectivity of the reaction was found to be determined by the cross-coupling carbon-carbon bond forming reaction, rather than any precoordination species. It appears that the lowest energy cross-coupling pathway requires a lesser degree of electronic reorganization in its transition state vs the lowest energy homocoupling pathway. This result was supported by stoichiometric Cr(V) kinetics, 13C kinetic isotope effects, and density functional theory (DFT) calculations. The understanding of the full landscape of this reaction allowed us to develop a general analysis to predict the regioselectivity of the cross-coupling reaction.
Chromium-Salen Catalyzed Cross-Coupling of Phenols: Mechanism and Origin of the Selectivity
Nieves-Quinones, Yexenia,Paniak, Thomas J.,Lee, Young Eun,Kim, Sun Min,Tcyrulnikov, Sergei,Kozlowski, Marisa C.
supporting information, p. 10016 - 10032 (2019/07/04)
A highly chemoselective phenol cross-coupling reaction catalyzed by a Cr-salen catalyst was developed. Kinetic studies showed that the oxidation of Cr(III) to Cr(V) is the rate-determining step of the reaction. In addition, experimental stoichiometric analysis showed that a high valent Cr(V) species is the active catalyst for this process. The selectivity of the reaction was found to be determined by the cross-coupling carbon-carbon bond forming reaction, rather than any precoordination species. It appears that the lowest energy cross-coupling pathway requires a lesser degree of electronic reorganization in its transition state vs the lowest energy homocoupling pathway. This result was supported by stoichiometric Cr(V) kinetics, 13C kinetic isotope effects, and density functional theory (DFT) calculations. The understanding of the full landscape of this reaction allowed us to develop a general analysis to predict the regioselectivity of the cross-coupling reaction.
Selective oxidative homo-and cross-coupling of phenols with aerobic catalysts
Lee, Young Eun,Cao, Trung,Torruellas, Carilyn,Kozlowski, Marisa C.
, p. 6782 - 6785 (2014/06/09)
Simple catalysts that use atom-economical oxygen as the terminal oxidant to accomplish selective ortho-ortho, ortho-para, or para-para homo-couplings of phenols are described. In addition, chromium salen catalysts have been discovered as uniquely effective in the cross-coupling of different phenols with high chemo-and regioselectivity.
