TY - JOUR
T1 - Strong Influence of the Nucleophile on the Rate and Selectivity of 1,2-Epoxyoctane Ring Opening Catalyzed by Tris(pentafluorophenyl)borane, B(C6F5)3
AU - Bennett, Charmaine K.
AU - Bhagat, Mihir N.
AU - Zhu, Youlong
AU - Yu, Ying
AU - Raghuraman, Arjun
AU - Belowich, Matthew E.
AU - Nguyen, Son Binh T.
AU - Notestein, Justin M.
AU - Broadbelt, Linda J.
PY - 2019/12/6
Y1 - 2019/12/6
N2 - Density functional theory (DFT) calculations, experimental data, and microkinetic modeling are used to extend a triple-pathway (Lewis acid, water-mediated, and alcohol-mediated) mechanism for tris(pentafluorophenyl)borane-catalyzed ring opening of 1,2-epoxyoctane by alkyl alcohol nucleophiles previously applied to 2-propanol to 1-propanol. Although simpler models may capture overall rates, the reaction schemes proposed here are required to explain the increasing regioselectivity to the primary product with conversion and the dependence of the overall regioselectivity on residual water concentration and additives as a function of reaction conditions. The model indicates that the different reaction conditions (nucleophile, water concentration, temperature, and conversion) lead to different amounts of flux through alcohol-mediated pathways, different speciation of tris(pentafluorophenyl)borane adducts, and differences among the inherent selectivities of water-mediated mechanisms.
AB - Density functional theory (DFT) calculations, experimental data, and microkinetic modeling are used to extend a triple-pathway (Lewis acid, water-mediated, and alcohol-mediated) mechanism for tris(pentafluorophenyl)borane-catalyzed ring opening of 1,2-epoxyoctane by alkyl alcohol nucleophiles previously applied to 2-propanol to 1-propanol. Although simpler models may capture overall rates, the reaction schemes proposed here are required to explain the increasing regioselectivity to the primary product with conversion and the dependence of the overall regioselectivity on residual water concentration and additives as a function of reaction conditions. The model indicates that the different reaction conditions (nucleophile, water concentration, temperature, and conversion) lead to different amounts of flux through alcohol-mediated pathways, different speciation of tris(pentafluorophenyl)borane adducts, and differences among the inherent selectivities of water-mediated mechanisms.
KW - DFT
KW - epoxide alcoholysis
KW - Lewis acid
KW - microkinetic modeling
KW - reaction mechanisms
KW - ring-opening reactions
KW - triarylboranes
KW - tris(pentafluorophenyl)borane
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U2 - 10.1021/acscatal.9b02607
DO - 10.1021/acscatal.9b02607
M3 - Article
AN - SCOPUS:85073124026
VL - 9
SP - 11589
EP - 11602
JO - ACS Catalysis
JF - ACS Catalysis
SN - 2155-5435
IS - 12
ER -