477773-68-5Relevant academic research and scientific papers
Gold-Catalyzed Asymmetric Thioallylation of Propiolates via Charge-Induced Thio-Claisen Rearrangement
Kim, Hanbyul,Jang, Jiwon,Shin, Seunghoon
, p. 20788 - 20795 (2020/11/27)
A gold(I)-catalyzed enantioselective thioallylation of propiolates with allyl sulfides is described. The key mechanistic element is a sulfonium-induced Claisen rearrangement which helps minimize the allyl dissociation and render higher enantioselectivity. This protocol features remarkable scope of the allyl moiety, allowing enantiocontrolled synthesis of all-carbon quaternary centers, and exhibits exceptional functional group compatibility with many Lewis bases and π-bonds. This intermolecular variant of Claisen rearrangement forges both C-S and C-C bonds concomitantly, providing efficient access to interesting optically active organosulfur compounds which can be transformed further through the vinyl sulfide as a functional handle. The rate of the reaction was zeroth order with respect to allyl sulfides, which suggested a reversible inhibition, providing a resting state for the catalyst. The Hammett plot displayed a correlation with σp values, suggesting a turnover-limiting sigmatropic rearrangement where decreased electron-density on sulfur accelerated the rearrangement.
Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
Romano, Ciro,Fiorito, Daniele,Mazet, Clément
, p. 16983 - 16990 (2019/10/28)
The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometalation using [Pd-H] or [Ru-H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, with excellent diastereo- and enantioselectivity.
A novel consecutive three-component Heck-isomerization-Wittig sequence by way of in situ generated aldehydes
Panther, Jesco,Roehrich, Adalbert,Mueller, Thomas J. J.
, p. 297 - 311 (2013/09/24)
A novel consecutive three-component four step synthesis of 5-(hetero)arylpent-2-enoates has been disclosed. Various (hetero)aryl iodides can be coupled with allyl alcohol under Heck conditions to give 3-(hetero)arylpropionaldehyde intermediates, which were transformed without isolation with in situ generated stabilized phosphorus ylides to furnish 5-(hetero)arylpent-2-enoates in moderate to excellent yield. This one-pot procedure circumvents the isolation of sensitive aldehydes and phosphorus ylides as intermediates and finally gives the product isomers with good to excellent E/Z and β/α selectivity. ARKAT-USA, Inc.
Manganese(III)-mediated phosphinoyl radical reactions for stereoselective synthesis of phosphinoylated tetrahydronaphthalenes
Pan, Xiang-Qiang,Wang, Lu,Zou, Jian-Ping,Zhang, Wei
, p. 7875 - 7877 (2011/09/12)
Reactions of diphenylphosphinoyl radicals with 5-aryl-2-pentenoates or β-phenylethylene styrenes generate trans-substituted tetrahydronaphthalenes through a cascade reaction sequence.
Iron tricarbonyl stabilized pentadienyl cation as initiator for cascade polycyclizations: A diastereoselective entry into octahydrophenanthrenes
Pearson, Anthony J.,Ghidu, Victor P.
, p. 8975 - 8978 (2007/10/03)
A new example is provided of completely diastereoselective polycyclization, affording the octahydrophenanthrene framework. Generation of an iron tricarbonyl stabilized pentadienyl carbocation is the triggering event of the cascade reaction. The carbocation is generated by anchimerically assisted regiospecific protonation of a double bond adjacent to the iron tricarbonyl diene moiety. Tetrafluoroboric acid ether complex appears to be the optimum reagent, affording good yields, even under catalytic conditions.
