- Development of BODIPY dyes with versatile functional groups at 3,5-positions from diacyl peroxides via Cu(ii)-catalyzed radical alkylation
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An efficient Cu(ii)-catalyzed, C-H alkylation of BODIPY with a variety of alkyl diacyl peroxides has been developed for the first time, providing a late-stage and straightforward method for controllable synthesis of monoalkylated and dialkylated BODIPYs via a radical process that otherwise is difficult to obtain by literature methods. This chemo- and site-selective transformation will allow for the introduction of a variety of functionalities on the BODIPY core for highly versatile tethering to receptors and to other molecules of interest.
- Tang, Bing,Lv, Fan,Chen, Kangkang,Jiao, Lijuan,Liu, Qingyun,Wang, Hua,Hao, Erhong
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- Decarboxylative C(sp3)?N cross-coupling of diacyl peroxides with nitrogen nucleophiles
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We have disclosed a new radical-mediated decarboxylative C(sp3)?N cross-coupling of diacyl peroxides with nitrogen nucleophiles. The primary and secondary alkyl radicals derived from corresponding diacyl peroxides were generated by copper catalysis or by merging copper catalysis and photoredox catalysis, respectively. Various N-alkyl nitrogen nucleophiles, including indazoles, triazoles, indoles, purine, carbazole, anilines, and sulfonamide, were provided with a broad substrate scope and good functional group tolerance.
- Tang, Zi-Liang,Ouyang, Xuan-Hui,Song, Ren-Jie,Li, Jin-Heng
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supporting information
p. 1000 - 1004
(2021/02/06)
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- Iron-Catalyzed Enantioselective Radical Carboazidation and Diazidation of α,β-Unsaturated Carbonyl Compounds
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Azidation of alkenes is an efficient protocol to synthesize organic azides which are important structural motifs in organic synthesis. Enantioselective radical azidation, as a useful strategy to install a C-N3 bond, remains challenging due to the inherently instability and unique structure of radicals. Here, we disclose an efficient enantioselective radical carboazidation and diazidation of α,β-unsaturated ketones and amides catalyzed by chiral N,N′-dioxide/Fe(OTf)2 complexes. An array of substituted alkenes was transformed to the corresponding α-azido carbonyl derivatives in good to excellent enantioselectivities, benefiting the preparation of chiral α-amino ketones, vicinal amino alcohols, and vicinal diamines. Control experiments and mechanistic studies proved the radical pathway in the reaction process. The DFT calculations showed that the azido transferred to the radical intermediate via an intramolecular five-membered transition state with the internal nitrogen of the Fe-N3 species.
- Dong, Shunxi,Feng, Xiaoming,He, Jun,Liu, Wen,Liu, Xiaohua,Pu, Maoping,Wu, Yun-Dong,Zhang, Tinghui
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supporting information
p. 11856 - 11863
(2021/08/16)
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- Cu-Catalyzed Alkylarylation of Vinylarenes with Masked Alkyl Electrophiles
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A Cu-catalyzed synthesis of a range of value-Added 1,1-diarylalkanes by radical alkylarylation of vinylarenes with alkyl peroxides as masked alkyl electrophiles is reported. The reaction features broad substrate scope, good functional group tolerance, and mild reaction conditions. Various bioactive molecules and key pharmaceutical intermediates have been easily synthesized by this method, demonstrating its synthetic value.
- Zhu, Xiaotao,Su, Muqiao,Zhang, Qi,Li, Yajun,Bao, Hongli
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supporting information
p. 620 - 625
(2020/01/02)
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- Radical alkylation of C(sp3)-H bonds with diacyl peroxides under catalyst-free conditions
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Herein, we describe a protocol for alkylation reactions of C(sp3)-H bonds with diacyl peroxides by means of a process involving cross-coupling between an alkyl radical and an α-Aminoalkyl radical. The mild, catalyst-And additive-free conditions make this protocol superior to previously reported C(sp3)-H alkylation strategies. The protocol was applied to 1,2,3,4-Tetrahydroisoquinolines and a tetrahydro-β-carboline derivative and could be carried out on a gram scale, indicating its utility for the alkylation of late-stage synthetic intermediates.
- Tian, Hao,Xu, Wentao,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 14813 - 14816
(2019/12/24)
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- Iron-Catalyzed Dehydrative Alkylation of Propargyl Alcohol with Alkyl Peroxides to Form Substituted 1,3-Enynes
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This paper reports a new method for the generation of substituted 1,3-enynes, whose synthesis by other methods could be a challenge. The dehydrative decarboxylative cascade coupling reaction of propargyl alcohol with alkyl peroxides is enabled by an iron catalyst and alkylating reagents. Primary, secondary, and tertiary alkyl groups can be introduced into 1,3-enynes, affording various substituted 1,3-enynes in moderate to good yields. Mechanistic studies suggest the involvement of a radical-polar crossover pathway.
- Ye, Changqing,Qian, Bo,Li, Yajun,Su, Min,Li, Daliang,Bao, Hongli
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supporting information
p. 3202 - 3205
(2018/06/11)
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- Copper-Catalyzed Decarboxylative Alkylation of Terminal Alkynes
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A copper-catalyzed decarboxylative alkylation of terminal alkynes under mild reaction conditions has been reported. Various alkyl diacyl peroxides were applied as the alkyl source for the formation of C(sp3)?C(sp) bond. A range of terminal alkynes including aryl alkynes and alkyl alkynes delivered the alkylated internal alkynes with good to high performances. Mechanism studies suggested that this reaction involves a free radical pathway. (Figure presented.).
- Ye, Changqing,Li, Yajun,Bao, Hongli
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supporting information
p. 3720 - 3724
(2017/09/18)
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- Iron-catalyzed C-H alkylation of heterocyclic C-H bonds
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An efficient, iron-catalyzed C-H alkylation of benzothiazoles by using alkyl diacyl peroxides and alkyl tertbutyl peresters which are readily accessible from carboxylic acids to synthesize 2-alkylbenzothiazoles is developed. This reaction is environmentally benign and compatible with a broad range of functional groups. Various primary, secondary, and tertiary alkyl groups can be efficiently incorporated into diverse benzothiazoles. The effectiveness of this method is illustrated by late-stage functionalization of biologically active heterocycles.
- Babu, Kaki Raveendra,Zhu, Nengbo,Bao, Hongli
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supporting information
p. 46 - 49
(2017/11/28)
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- Iron(III)-Catalyzed Ortho-Preferred Radical Nucleophilic Alkylation of Electron-Deficient Arenes
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The untraditional iron-catalyzed, ortho-preferred, radical alkylation of electron-deficient (hetero)arenes is reported. A variety of electron-deficient arenes were shown to react with various primary alkyl sources, producing the alkylated (hetero)arenes in good yields. This reaction might be an alkyl radical, nucleophilic aromatic substitution reaction, rather than the traditional electrophilic Friedel-Crafts reaction. HOMO-LUMO analysis and DFT studies on the key transition states underlying the regioselectivity are consistent with the observed reactions and the conclusions.
- Yu, Fei,Wang, Ting,Zhou, Huan,Li, Yajun,Zhang, Xinhao,Bao, Hongli
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supporting information
p. 6538 - 6541
(2017/12/26)
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- Copper-catalyzed regioselective 1,2-alkylesterification of dienes to allylic esters
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Copper catalyzed 1,2-alkylesterification of 1,3-dienes with diacyl peroxides affords branched allylic esters in excellent regioselectivity, including products with a newly generated fully substituted carbon center. The only byproduct is CO2. The reaction proceeds by a radical mechanism as suggested by spin trap and crossover experiments.
- Li, Yougui,Han, Yulong,Xiong, Haigen,Zhu, Nengbo,Qian, Bo,Ye, Changqing,Kantchev, Eric Assen B.,Bao, Hongli
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supporting information
p. 392 - 395
(2016/02/18)
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- The Surface of Silica as a Medium for the Radical and Ionic Decomposition of Diacyl Peroxides
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The rates of decomposition of β-phenylpropionyl peroxide 1, β-phenylisovaleryl peroxide 2, and β-phenylisovaleryl p-nitrobenzoyl peroxide 3 are much higher on silica surfaces than they are in solution.The products formed on silica surfaces are derived from both radical and ionic precursors except in the case of 3, for which the reaction may be entirely ionic.The relationships between the medium effects on the rates and on the products suggest that the ionic and radical parts of the reaction branch from a common polar intermediate.Both the ionic and radical products differ significantly from those formed in solution.In the neophyl radical, adsorption inhibits the migration of phenyl to form phenyl-tert-butyl radical.In the ionic reaction, there is extensive migration of methyl in competition with phenyl, in contrast to the behavior of neophyl derivatives in solvolysis reaction.Dihydrocoumarin, from 1, and dimethyldihydrocoumarin, from 2 and 3, are not formed at all in solution.Esters, which are often formed via carboxy inversion and related reactions when polar diacyl peroxides decompose in solution, appear to arise from electron transfer in radial-pair precursors.There is no evidence of carboxy inversion compounds or carbonic acid esters in the physically adsorbed products, although some RO-C(=O)+ groups (1-2percent) appear to be trapped by the silica.Rearranged and unrearranged neophyl cations are trapped more extensively as silyl ethers.Other ion-derived products are one of the phenylisobutylenes, several phenylbutenes, and the carboxylic acids.Coadsorbed oxygen or acetonitrile alters the product distribution partly by trapping radicals and partly by site preemption effects.
- Leffler, J.E.,Barbas, J.T.
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p. 7768 - 7773
(2007/10/02)
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