220652-97-1Relevant academic research and scientific papers
De Novo Construction of Substituted Terephthalates via Phosphine Catalyzed Domino Benzannulation Reactions
Wang, Dan,Lin, Junhui,Zhu, Yannan,Huang, You
, p. 1873 - 1877 (2021)
The robustness of phosphine catalysis enabling the domino benzannulation reactions of allenoates with enamines is described. A broad array of substituted terephthalates were delivered under simple and practical reaction conditions. Furthermore, the reaction could be carried out on a gram scale with higher yield, and various conversions of the terephthalate products demonstrate the versatility of this transformation. (Figure presented.).
Au(I) Catalyzed Synthesis of Densely Substituted Pyrazolines and Dihydropyridines via Sequential Aza-Enyne Metathesis/6π-Electrocyclization
Sugimoto, Kenji,Kosuge, Shuto,Sugita, Takae,Miura, Yuka,Tsuge, Kiyoshi,Matsuya, Yuji
, p. 3981 - 3985 (2021/05/26)
A gold(I) autotandem catalysis protocol is reported for the de novo synthesis of densely substituted pyrazolines and dihydropyridines from the corresponding imine derivatives in a highly regioselective fashion via a one-pot aza-enyne metathesis/6π-electrocyclization sequence. The substituents on the nitrogen atom of the imine perfectly control the reaction pathways from the pivotal 1-azabutadiene intermediate; thus, carbazates were converted into pyrazolines via 6π-electrocyclization of α,β-unsaturated hydrazones, while aryl imines provided dihydropyridines via 6π-electrocyclization of 3-azahexatrienes.
Oxidant- and additive-free simple synthesis of 1,1,2-triiodostyrenes by one-pot decaroboxylative iodination of propiolic acids
Ghosh, Subhankar,Ghosh, Rajat,Chattopadhyay, Shital K.
supporting information, (2020/09/15)
A metal- and oxidant-free facile synthesis of a range of 1,1,2-triiodostryrene derivatives has been developed which utilizes a simple decarboxylative triiodination of propiolic acids using molecular iodine and sodium acetate in a one-pot manner. Electron-
Alkynylboration Reaction Leading to Boron-Containing π-Extended cis-Stilbenes as a Highly Tunable Fluorophore
Nogami, Marina,Hirano, Keiichi,Morimoto, Kensuke,Tanioka, Masaru,Miyamoto, Kazunori,Muranaka, Atsuya,Uchiyama, Masanobu
supporting information, p. 3392 - 3395 (2019/05/10)
An unprecedented boron-containing fluorophore, π-extended cis-stilbene, obtained via alkynylboration reaction of alkynamide is reported. Boron-containing π-extended cis-stilbenes emit fluorescence with high quantum yields in the solid state and exhibit aggregation-induced emission enhancement. The broad substrate scope of the alkynylboration reaction offers facile access to electronically diverse structures, enabling fine-tuning of light absorption/emission characteristics. The boron-containing π-extended cis-stilbene with a diphenylamino group displays solvatofluorochromism via an intramolecular charge-transfer transition.
Trans-Hydroboration of Propiolamides: Access to Primary and Secondary (E)-β-Borylacrylamides
Grams, R. Justin,Fritzemeier, Russell G.,Slebodnick, Carla,Santos, Webster L.
supporting information, p. 6795 - 6799 (2019/08/26)
A base-mediated trans-hydroboration of propiolamides that provides access to previously elusive primary and secondary (E)-β-borylacrylamide products has been developed. In the presence of n-butyllithium and pinacolborane, complete regioselectivity and ste
Transition Metal-Free Trans Hydroboration of Alkynoic Acid Derivatives: Experimental and Theoretical Studies
Fritzemeier, Russell,Gates, Ashley,Guo, Xueying,Lin, Zhenyang,Santos, Webster L.
, p. 10436 - 10444 (2018/07/21)
We report a phosphine-catalyzed trans hydroboration of alkynoate esters and amides. The reaction proceeds under mild conditions with exclusive (E)-selectivity to afford (E)-β-boryl acrylates and (E)-β-boryl acrylamides in good to excellent yields. The reaction is tolerant of a variety of functional groups and allows efficient access to novel oxaboroles as well as a pargyline derivative (MAO inhibitor). Theoretical calculations suggest an internal hydride generates a phosphonium allenoxyborane followed by the formation of a key phosphonocyclobutene intermediate that collapses in a stereoselective, rate-limiting step.
Rhodium(III)-Catalyzed Redox-Neutral Cascade [3 + 2] Annulation of N-Phenoxyacetamides with Propiolates via C-H Functionalization/Isomerization/Lactonization
Pan, Jin-Long,Chen, Chao,Hao, Yu,Liu, Chang,Bai, He-Yuan,Ding, Jun,Zhang, Shu-Yu,Wang, Li-Ren,Xie, Peipei,Xia, Yuanzhi
supporting information, p. 7131 - 7136 (2018/12/14)
A Rh(III)-catalyzed cascade [3 + 2] annulation of N-phenoxyacetamides with propiolates under mild conditions using the internal oxidative O-N bond as the directing group has been achieved. This catalytic system provides a regio- and stereoselective access to benzofuran-2(3H)-ones bearing exocyclic enamino motifs with exclusive Z configuration selectivity, acceptable to good yields and good functional group compatibility. Mechanistic investigations by experimental and density functional theory studies suggest that a consecutive process of C-H functionalization/isomerization/lactonization is likely to be involved in the reaction.
Salt-Free Strategy for the Insertion of CO2 into C?H Bonds: Catalytic Hydroxymethylation of Alkynes
Wendling, Timo,Risto, Eugen,Krause, Thilo,Goo?en, Lukas J.
supporting information, p. 6019 - 6024 (2018/03/27)
A copper(I) catalyst enables the insertion of carbon dioxide into alkyne C?H bonds by using a suitable organic base with which hydrogenation of the resulting carboxylate salt with regeneration of the base becomes thermodynamically feasible. In the presence of catalytic copper(I) chloride/4,7-diphenyl-1,10-phenanthroline, polymer-bound triphenylphosphine, and 2,2,6,6-tetramethylpiperidine as the base, terminal alkynes undergo carboxylation at 15 bar CO2 and room temperature. After filtration, the ammonium alkynecarboxylate can be hydrogenated to the primary alcohol and water at a rhodium/molybdenum catalyst, regenerating the amine base. This demonstrates the feasibility of a salt-free overall process, in which carbon dioxide serves as a C1 building block in a C?H functionalization.
Synthesis of novel benzochromenes using triarylphosphines, alkyl X-phenylpropiolates and 2-hydroxy-1-naphthaldehyde
Gholami, Hamid Reza,Asghari, Sakineh
, p. 206 - 209 (2018/05/26)
The reactions of a series of alkyl X-phenylpropiolates with 2-hydroxy-1-naphthaldehyde and triphenylphosphine led to benzochromenes in moderate yields. When the reactions were performed in the presence of bis(4-methoxyphenyl)phenylphosphine instead of tri
Application and scope of Schreiber's gold(I)-catalyzed α-pyrone synthesis to ring a aromatic podolactones
Sánchez-Larios, Eduardo,Giacometti, Robert D.,Hanessian, Stephen
supporting information, p. 5664 - 5669 (2014/11/08)
Schreiber's gold(I)-catalyzed synthesis of α-pyrones was adapted to the total synthesis of a ring A aromatic podolactone, urbalactone. The scope of the acetylenic ester partner in the formation of α-pyrones was studied. The total synthesis features, as ke
