1556-08-7Relevant articles and documents
Spectroscopic Analyses on Reaction Intermediates Formed during Chlorination of Alkanes with NaOCl Catalyzed by a Nickel Complex
Draksharapu, Apparao,Codolà, Zoel,Gómez, Laura,Lloret-Fillol, Julio,Browne, Wesley R.,Costas, Miquel
, p. 10656 - 10666 (2015)
The spectroscopic, electrochemical, and crystallographic characterization of [(Me,HPyTACN)NiII(CH3CN)2](OTf)2 (1) (Me,HPyTACN = 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane, OTf = CF3SO3) is described together with its reactivity with NaOCl. 1 catalyzes the chlorination of alkanes with NaOCl, producing only a trace amount of oxygenated byproducts. The reaction was monitored spectroscopically and by high resolution electrospray-mass spectrometry (ESI-MS) with the aim to elucidate mechanistic aspects. NaOCl reacts with 1 in acetonitrile to form the transient species [(L)NiII-OCl(S)]+ (A) (L = Me,HPyTACN, S = solvent), which was identified by ESI-MS. UV/vis absorption, electron paramagnetic resonance, and resonance Raman spectroscopy indicate that intermediate A decays to the complex [(L)NiIII-OH(S)]2+ (B) presumably through homolytic cleavage of the O-Cl bond, which liberates a Cl? atom. Hydrolysis of acetonitrile to acetic acid under the applied conditions results in the formation of [(L)NiIII-OOCCH3(S)]2+ (C), which undergoes subsequent reduction to [(L)NiII-OOCCH3(S)]2+ (D), presumably via reaction with OCl- or ClO2-. Subsequent addition of NaOCl to [(L)NiII-OOCCH3(S)]+ (D) regenerates [(L)NiIII-OH(S)]2+ (B) to a much greater extent and at a faster rate. Addition of acids such as acetic and triflic acid enhances the rate and extent of formation of [(L)NiIII-OH(S)]2+ (B) from 1, suggesting that O-Cl homolytic cleavage is accelerated by protonation. Overall, these reactions generate Cl? atoms and ClO2 in a catalytic cycle where the nickel center alternates between Ni(II) and Ni(III). Chlorine atoms in turn react with the C-H bonds of alkanes, forming alkyl radicals that are trapped by Cl? to form alkyl chlorides.
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Traynham,J.G.,Couvillon,T.M.
, p. 3205 - 3211 (1967)
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Allinger,N.L.,Tushaus,L.A.
, p. 2051 - 2059 (1967)
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A General Strategy for Aliphatic C-H Functionalization Enabled by Organic Photoredox Catalysis
Margrey, Kaila A.,Czaplyski, William L.,Nicewicz, David A.,Alexanian, Erik J.
supporting information, p. 4213 - 4217 (2018/04/05)
Synthetic transformations that functionalize unactivated aliphatic C-H bonds in an intermolecular fashion offer unique strategies for the synthesis and late-stage derivatization of complex molecules. Herein we report a general approach to the intermolecular functionalization of aliphatic C-H bonds using an acridinium photoredox catalyst and phosphate salt under blue LED irradiation. This strategy encompasses a range of valuable C-H transformations, including the direct conversions of a C-H bond to C-N, C-F, C-Br, C-Cl, C-S, and C-C bonds, in all cases using the alkane substrate as the limiting reagent. Detailed mechanistic studies are consistent with the intermediacy of a putative oxygen-centered radical as the hydrogen atom-abstracting species in these processes.
Silica gel-mediated hydrohalogenation of unactivated alkenes using hydrohalogenic acids under organic solvent-free conditions
Tanemura, Kiyoshi
supporting information, p. 4293 - 4298 (2018/11/10)
Silica gel-mediated hydrochlorination of unactivated alkenes using 35% hydrochloric acid under organic solvent-free conditions proceeded to give the corresponding chlorides in good yields. Hydrobromination or hydriodination using 47% hydrobromic acid or 55% hydriodic acid afforded the corresponding halides, respectively. Silica gel could be recycled five times without any significant loss of activities.
