1576-98-3Relevant articles and documents
Influence of the N→Ru Coordinate Bond Length on the Activity of New Types of Hoveyda-Grubbs Olefin Metathesis Catalysts Containing a Six-Membered Chelate Ring Possessing a Ruthenium-Nitrogen Bond
Alekseeva, Kseniia A.,Antonova, Alexandra S.,Grigoriev, Mikhail S.,Kumandin, Pavel A.,Nikitina, Eugeniya V.,Novikov, Roman A.,Polyanskii, Kirill B.,Sinelshchikova, Anna A.,Vasilyev, Kirill A.,Zubkov, Fedor I.
, p. 4599 - 4607 (2020)
An efficient approach to the synthesis of new types of Hoveyda-Grubbs catalysts containing an N→Ru bond in a six-membered chelate ring is proposed. The synthesis of the organometallic compounds is based on the interaction of ready accessible 2-vinylbenzylamines and 1,3-bis(2,4,6-trimethylphenyl)-2-trichloromethylimidazolidine ligands with dichloro(3-phenyl-1H-inden-1-ylidene)bis(tricyclohexylphosphane)ruthenate, and it afforded the target ruthenium complexes in 70-80% yields. Areas of practical utility and potential applications of the obtained chelates were highlighted by tests of the catalysts in different olefin cross-metathesis (CM) and ring-closing-metathesis (RCM) reactions. These experiments revealed a high catalytic performance (up to 10-2 mol %) of all the synthesized structures in a broad temperature range. The structural peculiarities of the resultant ruthenium catalysts were thoroughly investigated by X-ray crystallography, which allowed making a reliable correlation between the structure of the metallo-complexes and their catalytic properties. It was proved that the bond length between ruthenium and nitrogen in the six-membered chelate ring has the greatest effect on the stability and efficiency of the catalyst. As a rule, the shorter and stronger the N→Ru bond, the higher the stability of the complex and the worse its catalytic characteristics. In turn, the coordination N→Ru bond length can be finely tuned and varied over a wide range of values by changing the steric volume of the cyclic substituents at the nitrogen atom, which will make it possible, as appropriate, to obtain in the future metal complexes with predictable stability and the required catalytic activity. Also, it was found that complexes in which the nitrogen atom is included in the morpholine or isoquinoline rings are the most efficient catalysts in this series. An attempt to establish a correlation between the N→Ru bond length and the 1H and 13C chemical shifts in the Ru═CH fragment has been made.
Effect of a proximal oxygen substituent on the efficacy of ruthenium-catalyzed cross-metathesis and RCM
Maishal, Tarun K,Sinha-Mahapatra, Dilip K,Paranjape, Kavita,Sarkar, Amitabha
, p. 2263 - 2267 (2002)
Ruthenium-catalyzed cross-metathesis of various derivatives of 1,2-dihydroxy-3-butene reveals that cyclic acetals are best suited as substrates compared to acyclic diethers or diacetates, while RCM is relatively insensitive to the presence of allylic or homoallylic hydroxy or acetoxy groups.
Palladium(0)-catalyzed isomerization of (Z)-1,4-diacetoxy-2-butene - Dependence of η1- or η3-allylpalladium as a key intermediate on the solvent polarity
Bouquillon, Sandrine,Muzart, Jacques
, p. 3301 - 3305 (2001)
In the presence of Pd(PPh3)4, (Z)-1,4-diacetoxy-2-butene is selectively isomerized to (E)-1,4-diacetoxy-2-butene in THF while both (E)-1,4-diacetoxy-2-butene and 1,2-diacetoxy-3-butene are obtained in DMF. Evidence to support the involvement of an η1-allylpalladium in the former solvent and of a cationic η3-allylpalladium in the latter as the keys intermediates is presented.
Process for preparation of 4-acetoxy-2-methyl-2-butene-1-aldehyde and intermediates thereof
-
Paragraph 0055-0056; 0065-0066; 0072-0073; 0079-0080, (2021/06/09)
The invention relates to the technical field of organic synthesis, and discloses a method for preparing 4-acetoxy-2-methyl-2-butene-1-aldehyde and an intermediate thereof. The method comprises the following steps: (1) in the presence of an esterification reagent, carrying out esterification reaction on 1, 4-butenediol to obtain 1, 4-butenediol diacetate; (2) in the optional presence of a first catalyst, carrying out an isomerization reaction on the 1, 4-butenediol diacetate to obtain 3, 4-diacetoxy-1-butene; (3) in the presence of a phosphorus-containing ligand and a rhodium catalyst and/or a cobalt catalyst, carrying out hydroformylation reaction on the 3, 4-diacetoxy-1-butene, carbon monoxide and hydrogen to obtain 2-methyl-3, 4-diacetoxy-1-butyraldehyde; (4) in the optional presence of a third catalyst, carrying out an elimination reaction on the 2-methyl-3, 4-diacetoxyl-1-butyraldehyde to obtain the 4-acetoxyl-2-methyl-2-butene-1-aldehyde. The method provided by the invention has the advantages of mild reaction conditions, environmental friendliness and high yield.
Stereoselective Dynamic Cyclization of Allylic Azides: Synthesis of Tetralins, Chromanes, and Tetrahydroquinolines
Porter, Matthew R.,Shaker, Rami M.,Calcanas, Cristian,Topczewski, Joseph J.
supporting information, p. 1211 - 1214 (2018/02/09)
This report describes the stereoselective synthesis of 3-azido-tetralins, -chromanes, and -tetrahydroquinolines via a tandem allylic azide rearrangement/Friedel-Crafts alkylation. Exposure of allylic azides with a pendant trichloroacetimidate to catalytic quantities of AgSbF6 proved optimal for this transformation. This cascade successfully differentiates the equilibrating azide isomers, providing products in excellent yield and selectivity (>25 examples, up to 94% yield and >25:1 dr). In many cases, the reactive isomer is only a trace fraction of the equilibrium mixture, keenly illustrating the dynamic nature of these systems. We demonstrate the utility of this process via a synthesis of hasubanan.
