Cyclic Iodine Reagents Enable Allylic Alcohols for Alkyl Boronate Addition/Rearrangement by Photoredox Catalysis
作者:Mingshang Liu、Hanchu Huang、Yiyun Chen
DOI:10.1002/cjoc.201800461
日期:2018.12
iodine(III) reagents enable the synthesis of cyclopentanones, cyclohexanones, and dihydrofuranones bearing α‐quaternary centers by photoredox catalysis. The reaction proceeds by the formation of the novel cyclic iodine(III) reagent‐allylic alcohol complex, which enables the first alkyl boronate addition and semi‐pinacol rearrangement of allylic alcohols with dual alcohol and olefin activation. The reaction
azole heterocycles through Pd-Cu-catalyzed C-H bond activation has been reported using alkenyl bromides as the coupling partners. The reaction enables the introduction of various mono-, di-, or trisubstituted alkenyl bromides as well as a benzyl chloride to the caffeine core.
triorganocerium reagents and their application in catalyst‐free Zweifel olefinations. These unique cerium species were generated through novel exchange reactions of organohalides with n‐Bu3Ce reagents. The adequate electronegativity of cerium allowed for compensating the disadvantages of both usually functional‐group‐sensitive organolithium species and less reactive organomagnesium reagents. Exchange reactions
描述了三有机铈试剂的原位形成及其在无催化剂的Zweifel烯烃中的应用。这些独特的铈物种是通过有机卤化物与n- Bu 3 Ce试剂的新型交换反应生成的。铈具有足够的负电性,可以弥补通常对官能团敏感的有机锂物质和反应性较低的有机镁试剂的缺点。在芳基和烯基溴上进行交换反应,从而实现手性硼频哪醇酯的对映体特异性转化。最终,这些新的有机铈物种参与了可选择性和空间受阻的酮的选择性1,2-加成反应。