内部烯烃的双电子或单电子介导的双官能化代表了通过同时形成两个连续的 C sp 3立构中心来组装分子复杂性的直接方法。尽管外消旋形式已被广泛探索,但不对称变体,尤其是那些涉及开壳层以 C 为中心的自由基物种的变体,在数量和范围上都受到更多限制。在这里,我们描述了对映体富集的芳基亚磺酰胺作为一体化试剂,用于烯烃的有效不对称、分子间氨芳基化。在温和的光氧化还原条件下,芳基亚磺酰胺在双键上进行氮加成,然后芳环发生 1,4-易位,在单一操作中产生对映体富集形式的相应氨基芳基化加合物。亚磺酰基在此充当无痕手性助剂,因为它在温和的反应条件下原位消除。光学纯的 β,β-二芳基乙胺、芳基-α,β-乙二胺和 α-芳基-β-氨基醇是药物、生物活性天然产物和过渡金属配体中的突出基序,因此可以获得优异的区域、相对和绝对的立体声控制。
Retracted Article: Monodisperse CuB<sub>23</sub> nanoparticles grown on graphene as highly efficient catalysts for unactivated alkyl halide Heck coupling and levulinic acid hydrogenation
作者:Shi Yan Fu、Yuan Zhi Li、Wei Chu、Chun Li、Dong Ge Tong
DOI:10.1039/c4cy01331j
日期:——
Monodisperse CuB23 nanoparticles grown on graphene exert exceedingly high activity towards unactivated alkyl halide Heck coupling and levulinic acid hydrogenation.
1,1-Disubstituted olefin synthesis via Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides
作者:Xiao-Yu Lu、Jing-Hui Liu、Xi Lu、Zheng-Qi Zhang、Tian-Jun Gong、Bin Xiao、Yao Fu
DOI:10.1039/c6cc00176a
日期:——
A Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides is described.
描述了炔烃与卤代烷的Ni催化的Markovnikov加氢烷基化。
Alkylboronic acids as alkylating agents: photoredox-catalyzed alkylation reactions assisted by K<sub>3</sub>PO<sub>4</sub>
作者:Fuyang Yue、Henan Ma、Hongjian Song、Yuxiu Liu、Jianyang Dong、Qingmin Wang
DOI:10.1039/d2sc05521j
日期:——
alkylboronic acids in organic synthesis, their utility as alkyl radical precursors in visible-light-induced photocatalytic reactions is limited by their high oxidation potentials. In this study, we demonstrated that an inorganophosphorus compound can modulate the oxidation potentials of alkylboronic acids so that they can act as alkyl radical precursors. We propose a mechanism based on the results of fluorescence
尽管烷基硼酸在有机合成中无处不在,但它们在可见光诱导的光催化反应中作为烷基自由基前体的用途受到其高氧化电位的限制。在这项研究中,我们证明了一种无机磷化合物可以调节烷基硼酸的氧化电位,使其可以作为烷基自由基前体。我们根据荧光猝灭实验、电化学实验、 11 B 和31的结果提出了一种机制P NMR 光谱和其他技术。此外,我们描述了一种简单可靠的烷基化方法,该方法具有良好的官能团耐受性,可用于直接 C-B 氯化、氰化、乙烯基化、炔基化和烯丙基化,以及衍生药物分子的后期功能化。值得注意的是,烷基硼酸可以在硼频哪醇酯的存在下被选择性地激活。
Substituent effects for the olefination of aldehydes by zirconium metalloazines
作者:Georgia M. Arvanitis、Jeffrey Schwartz
DOI:10.1021/om00145a030
日期:1987.2
Energy Transfer from CdS QDs to a Photogenerated Pd Complex Enhances the Rate and Selectivity of a Pd-Photocatalyzed Heck Reaction
作者:Zhengyi Zhang、Cameron R. Rogers、Emily A. Weiss
DOI:10.1021/jacs.9b11278
日期:2020.1.8
mol% CdS QDs, which have an emission spectrum that overlaps the absorption spectrum of a key Pd(II)alkyliodide intermediate, the reaction proceeds with 82% yield for the Heck product at 0.5 mol% loading of Pd catalyst; no product forms at this loading without a sensitizer. A radical trapping experiment and steady-state and transientoptical spectroscopies indicate that the QDs transfer energy to a Pd(II)alkyliodide