64754-65-0Relevant academic research and scientific papers
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.
Oxidative coupling of alkenes with amides using peroxides: Selective amide C(sp3)-H versus C(sp2)-H functionalization
Yang, Xu-Heng,Wei, Wen-Ting,Li, Hai-Bing,Song, Ren-Jie,Li, Jin-Heng
supporting information, p. 12867 - 12869 (2014/12/11)
A new oxidative coupling of unactivated terminal alkenes with amides using peroxides is described, in which mono- and difunctionalization of alkenes are selectively achieved. In this reaction with amides, the chemoselectivity toward the functionalization of the C(sp3)-H bonds adjacent to the nitrogen atom or the functionalization of the carbonyl C(sp2)-H bonds across alkenes relies on the reaction conditions. This journal is
Copper-catalyzed bis(methoxycarbonyl)carbene reactions of α,β-unsaturated carboxamides
Merey, Goekce,Anac, Olcay
experimental part, p. 1053 - 1064 (2011/08/05)
The [Cu(acac)2]-catalyzed reactions of α,β- unsaturated carboxamides with dimethyl diazomalonate yielded dihydrofuran derivatives by a 1,5-electrocyclic reaction at C(β), and butadiene derivatives by carbene addition reaction at C(α) (Schemesa
Synthesis of β-monosubstituted α,β-unsaturated amides with z-selectivity using diphenylphosphonoacetamides
Kojima, Satoshi,Hidaka, Tsugihiko,Ohba, Yuko
, p. 515 - 523 (2007/10/03)
The utility of diphenylphosphonoacetamides [(PhO)2P(O)CH 2CONRR′] as Horner-Wadsworth-Emmons reagents was examined with five different patterns of substitution upon the amide nitrogen atom (2a: R, R′ = CH2Ph; 2b: R = CH2Ph, R′ = H; 2c: R = Me, R′ = OMe; 2d: R, R′ = Ph; 2e: R, R′ = (CH2) 4). The reaction of 2a was found to be Z-selective for aromatic aldehydes with selectivities up to 95:5. Reagent 2b led to reasonable selectivity for both benzaldehyde (85:15) and 3-phenylpropionaldehyde (87:13), while 2c was somewhat effective for only the latter alkyl aldehyde (83:17). Compounds 2d and 2e exhibited slightly lower selectivities compared with 2a.
Synthesis of α,β-unsaturated amides by olefin cross-metathesis
Choi, Tae-Lim,Chatterjee, Arnab K.,Grubbs, Robert H.
, p. 1277 - 1279 (2007/10/03)
Electronic and steric properties of the substituents on the amide nitrogen atom govern the yield and rate of the cross-metathesis between a variety of αβ-unsaturated amides and olefins with 1 as the catalyst. This influence is the result of deactivation of the catalyst by chelation of the carbonyl group to the metal. However, an increase in catalyst loading compensates for the chelation effect.
