- Formation of C(sp2) Boronate Esters by Borylative Cyclization of Alkynes Using BCl3
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BCl3is an inexpensive electrophile which induces the borylative cyclization of a wide range of substituted alkynes to regioselectively form polycycles containing synthetically versatile C(sp2) boronate esters. It proceeds rapidly, with good yields and is compatible with a range of functional groups and substitution patterns. Intermolecular 1,2-carboboration of alkynes is also achieved using BCl3to generate trisubstituted vinyl boronate esters.
- Warner, Andrew J.,Lawson, James R.,Fasano, Valerio,Ingleson, Michael J.
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- Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis
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The alkynylbenziodoxole derivatives are recently developed alkynylation reagents in organic synthesis, which demonstrate excellent radical alkynylation reactivity in photoredox catalysis reactions. Herein we report the synthesis of alkynylbenziodoxole derivatives with difluoro, monofluoro, monomethoxy, and dimethoxy substitution on the benziodoxole moiety, and investigated their radical alkynylation reactivity for the first time. A series of mechanistic experiments were conducted to study the radical acceptor and oxidative quencher reactivity of alkynylbenziodoxoles, in which unsubstituted alkynylbenziodoxoles played balancing roles in both processes, while electron-rich benziodoxole derivatives demonstrate synthetic advantages in some cases.
- Pan, Yue,Jia, Kunfang,Chen, Yali,Chen, Yiyun
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- Metal-Free Synthesis of Selenodihydronaphthalenes by Selenoxide-Mediated Electrophilic Cyclization of Alkynes
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A transition-metal-free, selenium mediated electrophilic cyclization reaction was realized through a one-pot procedure between simple alkynes and triflic anhydride-activated selenoxides to give selenium containing dihydronaphthalene products. This method gave good to very high yields for all products, including selenium-substituted phenanthrene, dihydroquinoline, 2H-chromene, and coumarin, which can be further transformed to other functionalized compounds.
- An, Shaoyu,Li, Pingfan,Zhang, Zhong
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p. 3059 - 3070
(2021/07/22)
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- Visible light-driven cross-coupling reactions of alkyl halides with phenylacetylene derivatives for C(sp3)-C(sp) bond formation catalyzed by a B12 complex
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Visible light-driven cross-coupling reactions of alkyl halides with phenylacetylene and its derivatives catalyzed by the cobalamin derivative (B12) with the [Ir(dtbbpy)(ppy)2]PF6 photocatalyst at room temperature are reported. The robust B12 catalyst and Ir photocatalyst provided high turnover numbers of over 33?000 for the reactions.
- Chen, Li,Kametani, Yohei,Imamura, Kenji,Abe, Tsukasa,Shiota, Yoshihito,Yoshizawa, Kazunari,Hisaeda, Yoshio,Shimakoshi, Hisashi
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supporting information
p. 13070 - 13073
(2019/11/11)
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- Recyclable heterogeneous metal foil-catalyzed cyclopropenation of alkynes and diazoacetates under solvent-free mechanochemical reaction conditions
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Silver and copper foil were found to be effective, versatile and selective heterogeneous catalysts for the cyclopropenation of terminal and internal alkynes under mechanochemical reaction conditions. This methodology enables the functionalization of a wide range of terminal or internal alkynes under ambient, aerobic, and solvent-free conditions. Finally, we have demonstrated a unique and versatile one-pot domino Sonogashira-cyclopropenation mechanochemical reaction for the formation of complex cyclopropenes.
- Chen, Longrui,Leslie, Devonna,Coleman, Michael G.,Mack, James
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p. 4650 - 4661
(2018/05/30)
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- Aluminum-Catalyzed Cross-Coupling of Silylalkynes with Aliphatic C-F Bonds
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We report the generation of aliphatic and benzylic acetylenes via reaction of primary, secondary, and tertiary aliphatic fluorides with various trimethylsilyl acetylides. These reactions are catalyzed by Al and B Lewis acids, most effectively by the extre
- Jaiswal, Amit K.,Goh, Kelvin K. K.,Sung, Simon,Young, Rowan D.
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supporting information
p. 1934 - 1937
(2017/04/11)
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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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p. 3720 - 3724
(2017/09/18)
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- Visible-Light-Induced Alkoxyl Radical Generation Enables Selective C(sp3)-C(sp3) Bond Cleavage and Functionalizations
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The alkoxyl radical is an important reactive intermediate in mechanistic studies and organic synthesis; however, its current generation from alcohol oxidation heavily relies on transition metal activation under strong oxidative conditions. Here we report the first visible-light-induced alcohol oxidation to generate alkoxyl radicals by cyclic iodine(III) reagent catalysis under mild reaction conditions. The β-fragmentation of alkoxyl radicals enables selective C(sp3)-C(sp3) bond cleavage and alkynylation/alkenylation reactions with various strained cycloalkanols, and for the first time with linear alcohols.
- Jia, Kunfang,Zhang, Fuyuan,Huang, Hanchu,Chen, Yiyun
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p. 1514 - 1517
(2016/02/20)
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- Manganese(III)-mediated selective diphenylphosphinoyl radical reaction of 1,4-diaryl-1-butynes for the synthesis of 2-phosphinoylated 3,4- dihydronaphathalenes
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A diphenylphosphinoyl radical-initiated sequential reaction of 1,4-diaryl-1-butynes and analogues is developed for the synthesis of 2-phosphinoylated 3,4-dihydronaphathalenes and related compounds.
- Li, Da-Peng,Pan, Xiang-Qiang,An, Li-Tao,Zou, Jian-Ping,Zhang, Wei
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p. 1850 - 1855
(2014/03/21)
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