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。
Regioselective Single-Electron Tsuji–Trost Reaction of Allylic Alcohols: A Photoredox/Nickel Dual Catalytic Approach
作者:Zheng-Jun Wang、Shuai Zheng、Eugénie Romero、Jennifer K. Matsui、Gary A. Molander
DOI:10.1021/acs.orglett.9b02473
日期:2019.8.16
A radical-mediated functionalization of allyl alcohol derived partners with a variety of alkyl 1,4-dihydropyridines via photoredox/nickel dual catalysis is described. This transformation transpires with high linear and E-selectivity, avoiding the requirement of harsh conditions (e.g., strong base, elevated temperature). Additionally, using aryl sulfinate salts as radical precursors, allyl sulfones
Here we report a visible-light-mediated and transition metal-free conjunctive olefination that uses an alkene ‘linchpin’ with a defined geometry to cross-couple complex molecular scaffolds that contain carboxylic acids and aldehydes. The chemistry merges two cornerstones of organic synthesis—namely, the Wittig reaction and photoredox catalysis—in a catalytic cycle that couples a radical addition process
Iridium-Catalyzed, Diastereoselective Dehydrogenative Silylation of Terminal Alkenes with (TMSO)<sub>2</sub>MeSiH
作者:Chen Cheng、Eric M. Simmons、John F. Hartwig
DOI:10.1002/anie.201304084
日期:2013.8.19
achieved under mild conditions with low catalyst loading. The diastereoselectivity of the reaction can be controlled by choosing the appropriate ancillary ligand (see scheme; coe=cyclooctene). The silylation products undergo further transformation such as oxidation or cross‐coupling.