title: Metal-Free α-C(sp³)-H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway.
abstract: The mechanistic pathway of TEMPO/I₂-mediated oxidative cyclization ofN,N-diaryl amino alcohols1was investigated. Based on direct empirical experiments, three key intermediates (aminium radical cation3, α-aminoalkyl radical4, and iminium5), 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 intermediate7.
authors.affiliation: Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Yeonsu-gu, Incheon 21936, Korea. azazay1@gmail.com.
authors.forename: Zakir
authors.initials: Z
authors.lastname: Ullah
authors.affiliation: Gachon Institute of Pharmaceutical Science & Department of Pharmacy, College of Pharmacy, Gachon University, Yeonsu-gu, Incheon 21936, Korea. kmh0515@gachon.ac.kr.
authors.forename: Mihyun
authors.initials: M
authors.lastname: Kim
mesh_terms: D000605:Amino Alcohols / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D000605:Amino Alcohols
keywords: 6-exo-trig; metal-free C–H activation; oxidative cyclization; tertiary amine; α-C(sp3)–H functionalization