Metal-Free α-C(sp3)–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway
Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Yeonsu-gu, Incheon 21936, Korea
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Academic Editor: Georgiy B. Shul’pin
Molecules 2017, 22(4), 547; https://doi.org/10.3390/molecules22040547
Received: 21 February 2017
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Revised: 18 March 2017
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Accepted: 24 March 2017
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Published: 29 March 2017
(This article belongs to the Special Issue Reactions of Hydrocarbons and other C‒H Compounds)
The mechanistic pathway of TEMPO/I2-mediated oxidative cyclization of N,N-diaryl amino alcohols 1 was investigated. Based on direct empirical experiments, three key intermediates (aminium radical cation 3, α-aminoalkyl radical 4, and iminium 5), four types of reactive species (radical TEMPO, cationic TEMPO, TEMPO-I, and iodo radical), and three types of pathways ((1) SET/PCET mechanism; (2) HAT/1,6-H transfer mechanism; (3) ionic mechanism) were assumed. Under the assumption, nine free energy diagrams were acquired through density functional theory calculations. From the comparison of solution-phase free energy, some possible mechanisms were excluded, and then the chosen plausible mechanisms were concretized using the more stable intermediate 7.
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Keywords:
α-C(sp3)–H functionalization; oxidative cyclization; tertiary amine; 6-exo-trig; metal-free C–H activation
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MDPI and ACS Style
Ullah, Z.; Kim, M. Metal-Free α-C(sp3)–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway. Molecules 2017, 22, 547. https://doi.org/10.3390/molecules22040547
AMA Style
Ullah Z, Kim M. Metal-Free α-C(sp3)–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway. Molecules. 2017; 22(4):547. https://doi.org/10.3390/molecules22040547
Chicago/Turabian StyleUllah, Zakir, and Mihyun Kim. 2017. "Metal-Free α-C(sp3)–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway" Molecules 22, no. 4: 547. https://doi.org/10.3390/molecules22040547
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