寻找替代贵金属的新型加氢催化剂的主要原因是对可持续性的关注以及3d过渡金属的独特机械特性。据报道,在还原剂存在下或在高温条件下,钴前体和特定配体的几种组合可提供活性加氢催化剂。这项研究报告了一种在不存在配体或表面活性剂的情况下通过还原商业CoCl 2制备小的单分散Co(0)纳米颗粒(3-4 nm)的新方法。在烯烃,炔烃,亚胺和杂芳烃(2–20 bar H 2)的氢化中观察到高催化活性。磁性使催化剂分离和多次回收成为可能。
Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: a general, regiospecific synthesis of α-aryl ketones
作者:Michael W. Justik、Gerald F. Koser
DOI:10.1016/j.tetlet.2004.06.029
日期:2004.8
The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding α-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric α-phenyl ketone pairs.
Reductive Activation and Hydrofunctionalization of Olefins by Multiphoton Tandem Photoredox Catalysis
作者:Milena L. Czyz、Mitchell S. Taylor、Tyra H. Horngren、Anastasios Polyzos
DOI:10.1021/acscatal.1c01000
日期:2021.5.7
of olefin feedstocks to architecturally complex alkanes represents an important strategy in the expedient generation of valuable molecules for the chemical and life sciences. Synthetic approaches are reliant on the electrophilicactivation of unactivated olefins, necessitating functionalization with nucleophiles. However, the reductive functionalization of unactivated and less activatedolefins with
Photochemical reactivity of α-phenyl β,γ-enones. Singlet 1,3-acyl shift, triplet aromatic di-π-methane (DPM) rearrangement and triplet aryl-carbonyl bridging
作者:Margareth J. C. M. Koppes、Peter C. J. Beentjes、Hans Cerfontain
DOI:10.1002/recl.19881070404
日期:——
The photochemistry of the series of α-phenyl β,γ-enones 6–10 has been studied under conditions of both direct (λ 300 nm) and triplet-sensitized irradiation with the aim of determining the reactivity patterns of these “multi”-chromophoric systems.
enones from olefins is described. The reaction was performed under visible-light irradiation in the presence of molecular oxygen and a photocatalyst. The reaction proceeded with various types of trisubstituted olefins to give enones in good yields with high regioselectivity. In particular, oxygen- and nitrogen-containing functional groups, heteroaromatic rings, and cyclopropanes were tolerated. Mechanistic
[3-(Ethylthio)allyl]titanium reagent generated easily from allyl ethyl sulfides condensed with aldehydes to give erythro-β-hydroxy sulfides in highly regio- and stereoselective manner. In contrast, crotyl ethyl sulfide reacted with aldehydes affording δ-hydroxy vinyl sulfide exclusively. The substitution pattern of the starting sulfide can have a pronounced effect on the selectivity in this condensation reaction