- Three-Component Alkene Difunctionalization by Direct and Selective Activation of Aliphatic C?H Bonds
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Catalytic alkene difunctionalization is a powerful strategy for the rapid assembly of complex molecules and has wide range of applications in synthetic chemistry. Despite significant progress, a compelling challenge that still needs to be solved is the installation of highly functionalized C(sp3)-hybridized centers without requiring pre-activated substrates. We herein report that inexpensive and easy-to-synthesize decatungstate photo-HAT, in combination with nickel catalysis, provides a versatile platform for three-component alkene difunctionalization through direct and selective activation of aliphatic C?H bonds. Compared with previous studies, the significant advantages of this strategy are that the most abundant hydrocarbons are used as feedstocks, and various highly functionalized tertiary, secondary, and primary C(sp3)-hybrid centers can be easily installed. The practicability of this strategy is demonstrated in the selective late-stage functionalization of natural products and the concise synthesis of pharmaceutically relevant molecules including Piragliatin.
- Xu, Sheng,Chen, Herong,Zhou, Zhijun,Kong, Wangqing
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supporting information
p. 7405 - 7411
(2021/02/20)
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- Photoinduced Cross-Coupling of Aryl Iodides with Alkenes
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A protocol for photoinduced cross-coupling of aryl iodides having polar π-functional groups or elongated π-conjugation with alkenes has been developed. The radical cascade mechanism involving generation of aryl radicals via C-I bond homolysis of photoexcited aryl iodides and their subsequent addition to alkenes is proposed. The method enables iodide-selective cross-coupling over other halogen leaving groups with functional group compatibility on both arene and alkene motifs.
- Liu, Yuliang,Li, Haoyu,Chiba, Shunsuke
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supporting information
p. 427 - 432
(2021/01/26)
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- Homobenzylic Oxygenation Enabled by Dual Organic Photoredox and Cobalt Catalysis
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Activation of aliphatic C(sp3)-H bonds in the presence of more activated benzylic C(sp3)-H bonds is often a nontrivial, if not impossible task. Herein we show that leveraging the reactivity of benzylic C(sp3)-H bonds to achieve reactivity at the homobenzylic position can be accomplished using dual organic photoredox/cobalt catalysis. Through a two-part catalytic system, alkyl arenes undergo dehydrogenation followed by an anti-Markovnikov Wacker-type oxidation to grant benzyl ketone products. This formal homobenzylic oxidation is accomplished with high atom economy without the use of directing groups, achieving valuable reactivity that traditionally would require multiple chemical transformations.
- McManus, Joshua B.,Griffin, Jeremy D.,White, Alexander R.,Nicewicz, David A.
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supporting information
p. 10325 - 10330
(2020/07/27)
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