Theoretical Studies on the Asymmetric Baeyer–Villiger Oxidation Reaction of 4‐Phenylcyclohexanone with m‐Chloroperoxobenzoic Acid Catalyzed by Chiral Scandium(III)–N,N′‐Dioxide Complexes |
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| Authors: | Dr. Na Yang Dr. Zhishan Su Prof. Dr. Xiaoming Feng Prof. Dr. Changwei Hu |
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| Affiliation: | Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064 (P. R. China) |
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| Abstract: | ![]()
The mechanism and enantioselectivity of the asymmetric Baeyer–Villiger oxidation reaction between 4‐phenylcyclohexanone and m‐chloroperoxobenzoic acid ( m ‐CPBA ) catalyzed by ScIII–N,N′‐dioxide complexes were investigated theoretically. The calculations indicated that the first step, corresponding to the addition of m ‐CPBA to the carbonyl group of 4‐phenylcyclohexanone, is the rate‐determining step (RDS) for all the pathways studied. The activation barrier of the RDS for the uncatalyzed reaction was predicted to be 189.8 kJ mol?1. The combination of an ScIII–N,N′‐dioxide complex and the m ‐CBA molecule can construct a bifunctional catalyst in which the Lewis acidic ScIII center activates the carbonyl group of 4‐phenylcyclohexanone while m ‐CBA transfers a proton, which lowers the activation barrier of the addition step (RDS) to 86.7 kJ mol?1. The repulsion between the m‐chlorophenyl group of m ‐CPBA and the 2,4,6‐iPr3C6H2 group of the N,N′‐dioxide ligand, as well as the steric hindrance between the phenyl group of 4‐phenylcyclohexanone and the amino acid skeleton of the N,N′‐dioxide ligand, play important roles in the control of the enantioselectivity. |
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| Keywords: | density functional calculations enantioselectivity oxidation reaction mechanisms scandium |
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