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C(sp3)–H functionalizations of light hydrocarbons using decatungstate photocatalysis in flow
Science ( IF 44.7 ) Pub Date : 2020-07-02 , DOI: 10.1126/science.abb4688
Gabriele Laudadio 1 , Yuchao Deng 1, 2, 3 , Klaas van der Wal 1 , Davide Ravelli 4 , Manuel Nuño 5 , Maurizio Fagnoni 4 , Duncan Guthrie 5 , Yuhan Sun 2, 3 , Timothy Noël 1
Affiliation  

Using hydrocarbons as reagents Adding small alkyl groups to complex molecules usually relies on alkyl halide reagents. Laudadio et al. now report a convenient method to add ethane and propane directly across conjugated olefins with no prefunctionalization or byproducts (see the Perspective by Oksdath-Mansilla). The C–H bond scission in this hydroalkylation is accomplished by a decatungstate photocatalyst that also acts as a hydrogen atom transfer agent to complete the process. The reaction, optimized under flow conditions, works with methane as well, albeit with lower efficiency. Science, this issue p. 92; see also p. 34 A photocatalytic method adds saturated hydrocarbons across conjugated olefins with no by-products. Direct activation of gaseous hydrocarbons remains a major challenge for the chemistry community. Because of the intrinsic inertness of these compounds, harsh reaction conditions are typically required to enable C(sp3)–H bond cleavage, barring potential applications in synthetic organic chemistry. Here, we report a general and mild strategy to activate C(sp3)–H bonds in methane, ethane, propane, and isobutane through hydrogen atom transfer using inexpensive decatungstate as photocatalyst at room temperature. The corresponding carbon-centered radicals can be effectively trapped by a variety of Michael acceptors, leading to the corresponding hydroalkylated adducts in good isolated yields and high selectivity (38 examples).

中文翻译:

在流动中使用十钨酸盐光催化对轻烃进行 C(sp3)-H 官能化

使用碳氢化合物作为试剂向复杂分子中添加小的烷基通常依赖于卤代烷试剂。劳达迪奥等。现在报告了一种无需预官能化或副产物直接在共轭烯烃中添加乙烷和丙烷的便捷方法(参见 Oksdath-Mansilla 的观点)。这种加氢烷基化反应中的 C-H 键断裂是由一种脱钨酸盐光催化剂完成的,该催化剂还充当氢原子转移剂以完成该过程。在流动条件下优化的反应也适用于甲烷,尽管效率较低。科学,这个问题 p。92; 另见第 34 光催化方法将饱和烃添加到共轭烯烃中,没有副产物。气态烃的直接活化仍然是化学界面临的主要挑战。由于这些化合物的内在惰性,通常需要苛刻的反应条件才能使 C(sp3)–H 键断裂,从而阻碍了合成有机化学中的潜在应用。在这里,我们报告了一种通用且温和的策略,在室温下使用廉价的十钨酸盐作为光催化剂,通过氢原子转移来激活甲烷、乙烷、丙烷和异丁烷中的 C(sp3)-H 键。相应的以碳为中心的自由基可以被各种迈克尔受体有效捕获,从而以良好的分离产率和高选择性(38 个例子)产生相应的氢化烷基化加合物。我们报告了一种通用且温和的策略,在室温下使用廉价的十钨酸盐作为光催化剂,通过氢原子转移来激活甲烷、乙烷、丙烷和异丁烷中的 C(sp3)-H 键。相应的以碳为中心的自由基可以被各种迈克尔受体有效捕获,从而以良好的分离产率和高选择性(38 个例子)产生相应的氢化烷基化加合物。我们报告了一种通用且温和的策略,在室温下使用廉价的十钨酸盐作为光催化剂,通过氢原子转移来激活甲烷、乙烷、丙烷和异丁烷中的 C(sp3)-H 键。相应的以碳为中心的自由基可以被各种迈克尔受体有效捕获,从而以良好的分离产率和高选择性(38 个例子)产生相应的氢化烷基化加合物。
更新日期:2020-07-02
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