53145-32-7Relevant academic research and scientific papers
N-Ethynylation of Anilides Decreases the Double-Bond Character of Amide Bond while Retaining trans-Conformation and Planarity
Yamasaki, Ryu,Morita, Kento,Iizumi, Hiromi,Ito, Ai,Fukuda, Kazuo,Okamoto, Iwao
, p. 10118 - 10122 (2019)
Activated amide bonds have been attracting intense attention; however, most of the studied moieties have twisted amide character. To add a new strategy to activate amide bonds while maintaining its planarity, we envisioned the introduction of an alkynyl group on the amide nitrogen to disrupt amide resonance by nN→Csp conjugation. In this context, the conformations and properties of N-ethynyl-substituted aromatic amides were investigated by DFT calculations, crystallography, and NMR spectroscopic analysis. In contrast to the cis conformational preference of N-ethyl- and vinyl-substituted acetanilides, N-ethynyl-substituted acetanilide favors the trans conformation in the crystal and in solution. It also has a decreased double bond character of the C(O)?N bond, without twisting of the amide. N-Ethynyl-substituted acetanilides undergo selective C(O)?N bond or N?C(sp) bond cleavage reactions and have potential applications as activated amides for coupling reactions or easily cleavable tethers.
Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
supporting information, p. 16470 - 16485 (2021/10/20)
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
Asymmetric Coupling of Carbon-Centered Radicals Adjacent to Nitrogen: Copper-Catalyzed Cyanation and Etherification of Enamides
Chen, Pinhong,Fu, Liang,Li, Yibiao,Liu, Guosheng,Zhang, Guoyu,Zhou, Song,Zou, Jianping
supporting information, p. 20439 - 20444 (2020/09/07)
The first copper-catalyzed asymmetric cyanation and etherification reactions of enamides have been established, where a carbon-centered radical adjacent to a nitrogen atom (CRAN) is enantioselectively trapped by a chiral copper(II) species. Moreover, the asymmetric cyanation of vinyl esters was disclosed as well. These reactions feature very mild reaction conditions and high functional group tolerance, and give a series of chiral α-cyano amides, α-cyano esters and α-hemiaminals in good yields with excellent enantioselectivity. The chiral α-cyano amides can be easily converted into enantioenriched 1,2-diamines and amino acids.
INVESTIGATION OF THE STRUCTURES OF AND THE INTRAMOLECULAR INTERACTIONS IN N-VINYLAMIDES BY MEANS OF MULTINUCLEAR NMR SPECTROSCOPIC (1H, 13C, 15N, 17O) DATA AND THE RESULTS OF QUANTUM-CHEMICAL CALCULATIONS
Afonin, A. V.,Trofimov, B. A.,Malysheva, S. F.,Vashchenko, A. V.
, p. 181 - 190 (2007/10/02)
As a result of an analysis of the parameters of the 1H, 13C, 15N, and 17O NMR spectra of a number of N-vinylanilides it was established that the phenyl ring is orthogonal to the plane of the amido group, while the vinyl and carbonyl groups are coplanar.Th
