6278-91-7Relevant articles and documents
Gold N-Heterocyclic Carbene Catalysts for the Hydrofluorination of Alkynes Using Hydrofluoric Acid: Reaction Scope, Mechanistic Studies and the Tracking of Elusive Intermediates
Bédard, Sandrine,Cavallo, Luigi,Falivene, Laura,Gauthier, Rapha?l,Nolan, Steven P.,Paquin, Jean-Fran?ois,Saab, Marina,Tzouras, Nikolaos V.,Van Hecke, Kristof,Zhang, Ziyun
, (2021/12/09)
An efficient and chemoselective methodology deploying gold-N-heterocyclic carbene (NHC) complexes as catalysts in the hydrofluorination of terminal alkynes using aqueous HF has been developed. Mechanistic studies shed light on an in situ generated catalyst, formed by the reaction of Br?nsted basic gold pre-catalysts with HF in water, which exhibits the highest reactivity and chemoselectivity. The catalytic system has a wide alkyl substituted-substrate scope, and stoichiometric as well as catalytic reactions with tailor-designed gold pre-catalysts enable the identification of various gold species involved along the catalytic cycle. Computational studies aid in understanding the chemoselectivity observed through examination of key mechanistic steps for phosphine- and NHC-coordinated gold species bearing the triflate counterion and the elusive key complex bearing a bifluoride counterion.
Preparation method of alkyl nitrile compound
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Paragraph 0159-0161, (2020/05/14)
The invention discloses a preparation method of an alkyl nitrile compound shown as formula I. The preparation method comprises the following step: in a solvent, in the presence of an additive and a catalyst, Zn (CN) 2 and an alkyl halide shown as formula II are subjected to a coupling reaction as shown in the specification to obtain the alkyl nitrile compound as shown in the formula I, wherein theadditive comprises an alkali, the catalyst comprises a nickel compound and a phosphine ligand; the nickel compound is one or more of zero-valent nickel, monovalent nickel salt and divalent nickel salt; when the nickel compound contains zero-valent nickel or divalent nickel salt, the catalyst further comprises a reducing agent. According to the preparation method disclosed by the invention, cyanation of an alkyl halide can be simply, conveniently and efficiently realized by using a cheap catalytic system, and the preparation method also has good functional group compatibility and substrate universality.
On the ozonolysis of unsaturated tosylhydrazones as a direct approach to diazocarbonyl compounds
Fegheh-Hassanpour, Younes,Ebrahim, Faisal,Arif, Tanzeel,Sintim, Herman O.,Claridge, Timothy D. W.,Amin, Nader T.,Hodgson, David M.
, p. 2876 - 2884 (2018/05/03)
The scope and limitations are described of reacting unsaturated tosylhydrazones with O3 followed by Et3N for the generation of 1,4- and 1,5-diazocarbonyl systems. Tosylhydrazones, from tosylhydrazide condensation with readily available δ- and ?-unsaturated α-ketoesters, led in the former case to a 2-pyrazoline whereas the latter cases led to α-diazo-?-ketoesters, although a terminal alkene produced a tetrahydropyridazinol. Using the ozonolysis-Et3N strategy, tosylhydrazones from cyclic enones give 2,5- and 2,6-diazoketones with aldehyde or ester functionality at the 1-position; the α-diazoaldehydes prefer the s-trans conformation, with a rotation barrier of 74 kJ mol-1 at 25 °C determined by NMR. This one-pot ozonolysis/Bamford-Stevens chemistry demonstrates both the tolerance of tosylhydrazones to ozone, and the subsequently added amine playing a dual role to directly transform the intermediate tosylhydrazone ozonides into products containing reactive diazo and ketone functionalities; such adducts are of particular value as precursors to cyclic carbonyl ylides for 1,3-dipolar cycloadditions.
