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Origins of the Enantio‐ and N/O Selectivity in the Primary‐Amine‐Catalyzed Hydroxyamination of 1,3‐Dicarbonyl Compounds with In‐Situ‐Formed Nitrosocarbonyl Compounds: A Theoretical Study
Author(s) -
Zhang Long,
Xu Changming,
Mi Xueling,
Luo Sanzhong
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201402720
Subject(s) - chemistry , chemoselectivity , regioselectivity , selectivity , enamine , catalysis , denticity , amination , nitroso , amine gas treating , enantioselective synthesis , reactivity (psychology) , hydrogen bond , organocatalysis , tertiary amine , medicinal chemistry , combinatorial chemistry , stereochemistry , organic chemistry , molecule , crystal structure , medicine , alternative medicine , pathology
Chemoselective control over N/O selectivity is an intriguing issue in nitroso chemistry. Recently, we reported an unprecedented asymmetric α‐amination reaction of β‐ketocarbonyl compounds that proceeded through the catalytic coupling of enamine carbonyl groups with in‐situ‐generated carbonyl nitroso moieties. This process was facilitated by a simple chiral primary and tertiary diamine that was derived from tert ‐leucine. This reaction featured high chemoselectivity and excellent enantioselectivity for a broad range of substrates. Herein, a computational study was performed to elucidate the origins of the enantioselectivity and N/O regioselectivity. We found that a bidentate hydrogen‐bonding interaction between the tertiary N + H and nitrosocarbonyl groups accounted for the high N selectivity, whilst the enantioselectivity was determined by Si ‐facial attack on the ( E )‐ and ( Z )‐enamines in a Curtin–Hammett‐type manner. The bidentate hydrogen‐bonding interaction with the nitrosocarbonyl moieties reinforced the facial selectivity in this process.