开发用于环境友好的有机转化的催化剂是一个非常活跃的研究领域。迄今为止报道的大多数催化剂都是基于过渡金属配合物。近年来,已经报道了由主族金属化合物催化的例子。在此,我们报告了一系列镁钳配合物,并通过 NMR 和 X 射线单晶衍射对其进行了表征。研究了通过芳构化/脱芳构化金属-配体合作对 H 2的可逆活化。利用所获得的配合物,在无碱条件下证明了前所未有的均相主族金属催化炔烃的半氢化和烯烃的氢化,得到Z-烯烃和烷烃分别作为产物,具有优异的收率和选择性。对照实验和 DFT 研究揭示了金属-配体合作参与氢化反应。该研究不仅为镁催化的炔烃半加氢和烯烃加氢提供了新途径,而且为主族金属配合物催化的其他化合物加氢提供了机会。
Nickel-Catalyzed Sonogashira Reactions of Non-activated Secondary Alkyl Bromides and Iodides
作者:Jun Yi、Xi Lu、Yan-Yan Sun、Bin Xiao、Lei Liu
DOI:10.1002/anie.201307069
日期:2013.11.18
A nicked reaction: The title reaction of terminal alkynes with non‐activated secondaryalkyliodides and bromides was accomplished for the first time. This reaction provides a new and practical approach for the synthesis of substituted alkynes (see scheme; cod=cyclo‐1,5‐octadiene).
Tandem Suzuki-Miyaura Cross-Coupling/Dehydrobromination of 1,1-Dibromoalkenes to Alkynes with a Cyclobutene-1,2-diylbis(imidazolium) Salt as Catalyst Precursor
作者:Andreas Schmidt、Alireza Rahimi
DOI:10.1055/s-0029-1218848
日期:2010.8
A cyclobutene-1,2-bis(imidazolium) salt proved to be an efficient catalyst precursor for one-pot tandem Suzuki-Miyaura/dehydrobromination reactions for the synthesis of alkynes starting from 1,1-dibromoalkenes and palladium(II) acetate, aryl boronic acids, and potassium tert-butoxide in toluene. Starting materials were prepared from aldehydes under Corey-Fuchs conditions.
Trialkylboranes are readily electrolyzed in an undivided cell by using two platinum plates as the electrodes in the presence of 1-alkynes in a tetrahydrofuran solution containing tetraalkylammonium halide to give corresponding alkynes in good yields. In the case of phenylacetylene, all alkyl groups of trialkylboranes are used for alkylation of the alkyne.
Cobalt(III)-Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation
作者:Malay Sen、Deepti Kalsi、Basker Sundararaju
DOI:10.1002/chem.201503643
日期:2015.10.26
Efficient, scalable cobalt‐catalyzed redox‐neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*CoIII neutral complex is employed as the catalyst for this redox‐neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible
据报道,高效,可扩展的钴催化的氧化还原中性[4 + 2]环化易于获得的肟和炔烃。所开发的合成方法学广泛适用,并能耐受包括杂环在内的各种官能团。稳定的Cp * Co III中性络合物用作该氧化还原-中性[4 + 2]环化反应的催化剂,该反应通过可逆的环金属化反应顺利进行,而无需任何外部氧化剂,仅产生水作为副产物。
Trifluoromethyl-Radical-Mediated Carbonylation of Alkanes Leading to Ethynyl Ketones
The carbonylation of alkanes 1 under radical-reaction conditions was examined by using ethynyl triflone A as the unimolecular chain-transfer (UMCT) reagent. Good to moderate yields of ethynylketones 2 were prepared by means of this three-component coupling reaction. Higher CO pressures as well as lower concentrations of triflone A improved the efficiency of the reaction over the direct addition, the