1566-65-0Relevant articles and documents
Iridium-Catalyzed Enantioselective Allylic Substitution of Enol Silanes from Vinylogous Esters and Amides
Chen, Ming,Hartwig, John F.
, p. 13972 - 13979 (2015)
The enol silanes of vinylogous esters and amides are classic dienes for Diels-Alder reactions. Here, we report their reactivity as nucleophiles in Ir-catalyzed, enantioselective allylic substitution reactions. A variety of allylic carbonates react with these nucleophiles to give allylated products in good yields with high enantioselectivities and excellent branched-to-linear ratios. These reactions occur with KF or alkoxide as the additive, but mechanistic studies suggest that these additives do not activate the enol silanes. Instead, they serve as bases to promote the cyclometalation to generate the active Ir catalyst. The carbonate anion, which was generated from the oxidative addition of the allylic carbonate, likely activates the enol silanes to trigger their activity as nucleophiles for reactions with the allyliridium electrophile. The synthetic utility of this method was illustrated by the synthesis of the anti-muscarinic drug, fesoterodine.
Stereoselective Synthesis of Vinylboronates by Rh-Catalyzed Borylation of Stereoisomeric Mixtures
Li, Shenhuan,Li, Jie,Xia, Tianlai,Zhao, Wanxiang
supporting information, p. 462 - 468 (2019/03/28)
The stereoselective preparation of vinylboronates via rhodium-catalyzed borylation of E/Z mixtures of vinyl actetates is described, and this method was also extended to synthesis of vinyldiboronates. These transformations feature high functional group compatibility and mild reaction conditions. Control experiments support a mechanism that involved a Rh-catalyzed borylation-isomerization sequence. The isomerization of (Z)-vinylboronates to (E)-isomers was also demonstrated.
A cost-effective shortcut to prepare organoselenium catalysts via decarboxylative coupling of phenylacetic acid with elemental selenium
Cao, Hongen,Liu, Mingxuan,Qian, Rongrong,Zhang, Xu,Yu, Lei
, (2018/11/25)
An interesting decarboxylative coupling reaction of phenylacetic acid with elemental selenium was discovered and employed for the preparation efficient organoselenium catalysts for Baeyer–Villiger reaction and oxidative deoximation reaction. Compared with the traditionally used Grignard reagent method, the decarboxylative coupling reaction with selenium powders provides a shortcut for the preparation of organoselenium catalysts free of carcinogenic organohalide starting materials, toxic and odorous selenol intermediates and magnesium salt solid wastes. This may be helpful for reducing the cost of selenium catalysts to facilitate the application of organoselenium-catalyzed green reactions in large-scale production.
Pd0.09Ce0.91O2-Δ: A sustainable ionic solid-solution precatalyst for heterogeneous, ligand free Heck coupling reactions
Mpungose, Philani P.,Sehloko, Neo I.,Dasireddy, Venkata D.B.C.,Mahadevaiah, Narayanappa,Maguire, Glenn E.,Friedrich, Holger B.
, p. 60 - 68 (2017/11/15)
A quick and easy method for the preparation of Pd2+ metal ion substituted in ceria, Pd0.09Ce0.91O2-δ solid solution oxide, is described. The Pd0.09Ce0.91O2-δ solid solution oxide was fully characterized by XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy. All characterization techniques strongly suggested that Pd2+ was successfully incorporated into the lattice structure of ceria. The effect of the reaction conditions on the catalytic properties of the Pd0.09Ce0.91O2-δ solid solution catalyst initially was studied in detail with the model Heck reaction of iodobenzene and methylacrylate to obtain optimum reaction conditions. The Pd0.09Ce0.91O2-δ solid solution catalyst then afforded substituted alkenes in good to excellent yields under these optimum reaction conditions. Steric and electronic effects were also studied, and were found to influence the catalytic activity. Characterization of the used catalyst suggests that Pd2+ in Pd0.09Ce0.91O2-δ is reduced in situ to Pd0 when employed in the Heck cross-coupling reactions. The catalyst was easily recovered by centrifuge and reused three times without significant loss of catalytic efficiency.
