氢化镍(II)配合物[(Me N 2 N)Ni-H](2)是通过[(Me N 2 N)Ni-OMe](6)与Ph 2 SiH 2反应合成的。 NMR和IR光谱以及X射线晶体学。2在溶液中不稳定,并通过两个反应途径分解。第一个途径是分子内NH还原性消除,得到Me N 2 NH和镍颗粒。第二种途径是分子间的,具有H 2,镍颗粒和五配位Ni(II)络合物[(Me N 2N)2 Ni](8)作为产物。2与丙酮和乙烯反应,分别形成[(Me N 2 N)Ni-O i Pr](9)和[(Me N 2 N)Ni-Et](10)。2也与卤代烷反应,生成卤化镍配合物和烷烃。使用[(Me N 2 N)Ni-Cl](1)作为催化剂,NaO i Pr或NaOMe作为碱,Ph 2 SiH 2或Me(EtO)2催化还原卤代烷SiH作为氢化物源。催化作用似乎是通过自由基机理进行的。
Cyanoborohydrides are efficient reagents in the reductive addition reactions of alkyl iodides and electron-deficient olefins. In contrast to using tinreagents, the reaction took place chemoselectively at the carbon–iodine bond but not at the carbon–bromine or carbon–chlorine bond. The reaction system was successfully applied to three-component reactions, including radical carbonylation. The rate constant
氰基硼氢化物是烷基碘化物和缺电子烯烃的还原加成反应中的有效试剂。与使用锡试剂相反,该反应在碳碘键上发生化学选择,而在碳溴或碳氯键上没有发生。该反应体系已成功应用于三组分反应,包括自由基羰基化。通过动力学竞争法,在25°C下从氰基硼氢化四丁基铵中伯烷基脱氢的速率常数估计为<1×10 4 M –1 s –1。该值比氢化三丁基锡的值小3个数量级。
Visible-Light-Mediated C–I Difluoroallylation with an α-Aminoalkyl Radical as a Mediator
作者:Fuyang Yue、Jianyang Dong、Yuxiu Liu、Qingmin Wang
DOI:10.1021/acs.orglett.1c02905
日期:2021.9.17
for direct visible-light-mediated C–I difluoroallylation reactions of α-trifluoromethyl arylalkenes with alkyliodides at room temperature with an α-aminoalkyl radical as a mediator. The protocol permits efficient functionalization of various α-trifluoromethyl arylalkenes with cyclic and acyclic primary, secondary, and tertiary alkyliodides and is scalable to the gram level. This mild protocol uses
Photoredox relay-catalyzed <i>gem</i>-difluoroallylation of alkyl iodides
作者:Yuanqiang Guo、Yunpeng Cao、Hongjian Song、Yuxiu Liu、Qingmin Wang
DOI:10.1039/d1cc04284j
日期:——
photocatalyst catalyze the reaction at different stages in the desired sequence under the same reaction conditions, and do not inhibit each other. This convenient method transforms a broad scope of alkyliodides into the corresponding gem-difluoroalkenes via C(sp3)–C(sp3) bond construction. The protocol has good functional group tolerance and is suitable for the late-stage modification of multifunctional
Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents
作者:Chi Wai Cheung、Peng Ren、Xile Hu
DOI:10.1021/ol501087m
日期:2014.5.2
cross-coupling of nonactivated secondary alkylbromides and iodides with alkynyl Grignardreagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.
Stereoselective Synthesis of Trisubstituted Alkenes through Sequential Iron-Catalyzed Reductive<i>anti</i>-Carbozincation of Terminal Alkynes and Base-Metal-Catalyzed Negishi Cross-Coupling
作者:Chi Wai Cheung、Xile Hu
DOI:10.1002/chem.201504049
日期:2015.12.7
stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron‐catalyzed anti‐selective carbozincation of terminal alkynes can be combined with a base‐metal‐catalyzed cross‐coupling to prepare trisubstituted alkenes in a one‐pot reaction and with high regio‐ and stereocontrol. Cu‐, Ni‐, and Co‐based catalytic systems are developed for the coupling of sp‐, sp2‐, and sp3‐hybridized