69709-49-5Relevant academic research and scientific papers
Ruthenium-indolizinone complexes as a new class of metalated heterocyclic compounds: Insight into unconventional alkyne activation pathways, revelation of unexpected electronic properties and exploration of medicinal application
Chung, Lai-Hon,Ng, Sze-Wing,Yeung, Chi-Fung,Shek, Hau-Lam,Tse, Sheung-Ying,Lo, Hoi-Shing,Chan, Siu-Chung,Tse, Man-Kit,Yiu, Shek-Man,Wong, Chun-Yuen
, p. 12838 - 12842 (2018)
The two series of ruthenium-indolizinone complexes prepared by Ru-mediated cyclization of pyridine-tethered alkynes represent the first examples of metalated indolizinone complexes. Joint experimental-theoretical investigation suggests an unconventional 5-endo-dig cyclization pathway as their formation mechanism. They also exhibit moderate cytotoxicity against several human cancer cell lines.
N-Heterocyclic Carbene-Catalyzed Synthesis of Ynones via C-H Alkynylation of Aldehydes with Alkynyliodonium Salts - Evidence for Alkynyl Transfer via Direct Substitution at Acetylenic Carbon
Rajkiewicz, Adam A.,Wojciechowska, Natalia,Kalek, Marcin
, p. 831 - 841 (2020/01/02)
Alkynylation of aldehydes with alkynyl(aryl)iodonium salts catalyzed by an N-heterocyclic carbene (NHC) has been developed. The application of the organocatalyst and the hypervalent iodine group transfer reagent allowed for metal-free C-H functionalization and C-C bond formation. The reaction proceeds under mild conditions, at -40 °C and in the presence of an amine base, providing access to an array of heteroaryl-propargyl ketones containing various substituents in good to excellent yields. The mechanism of the reaction was investigated by means of both experiments and density functional theory calculations. 13C-labeling and computations determined that the key alkynyl transfer step occurs via an unusual direct substitution at an acetylenic carbon, wherein an iodine-based leaving group is exchanged by a Breslow intermediate nucleophile. Moreover, kinetic studies revealed that the turnover-limiting step of the catalytic cycle is the generation of the Breslow intermediate, whereas the subsequent C-C bond formation is a fast process. These results are fully reproduced and rationalized by the calculated full free energy profile of the reaction, showing that the largest energy span is located between the protonated form of NHC catalyst and the transition state for the carbene attack on the aldehyde substrate.
One-pot regioselective synthesis of substituted pyrazoles and isoxazoles in PEG-400/water medium by Cu-free nano-Pd catalyzed sequential acyl Sonogashira coupling-intramolecular cyclization
Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Botla, Vinayak,Vadde, Ravinder,Jonnalagadda, Sreekantha Babu,Vasam, Chandra Sekhar
, p. 6471 - 6481 (2019/11/20)
Catalyst efficacy of in situ generated Pd-nanoparticles (PdNPs) in the regioselective one-pot synthesis of 3,5-di & 3,4,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles in environmentally benign PEG-400/H2O medium, which involves the sequential (i) Cu-free acyl-Sonogashira coupling (ASC) and (ii) intramolecular ynone-amine cyclization under PTC conditions was described. The results of controlled experiments support the operation of two sequential catalytic cycles (ASC/cyclization) and achievement of complementary/opposite regioselectivity via ynone-bound palladium in a one-pot approach. Moreover, the in situ PdNPs recovered after the first catalytic cycle of the one-pot reaction sequence have been reused again five times successively. Besides, prior to the above studies, the efficacy of some common Pd-N-heterocyclic carbene (Pd-NHC) complexes in catalyzing the same one-pot two-step reaction sequence (Cu-free ASC/cyclization) both in water and organic solvents was also optimized. In situ generation of PdNPs from above Pd-NHCs in water was also identified, but they are not reusable due to their large size distribution.
Palladium anchored on amine-functionalized K10 as an efficient, heterogeneous and reusable catalyst for carbonylative Sonogashira reaction
Chavan, Sujit P.,Varadwaj, G.Bishwa Bidita,Parida, Kulamani,Bhanage, Bhalchandra M.
, p. 237 - 245 (2015/10/12)
The present work describes the immobilization of palladium chloride (II) on the amine functionalized K10 support and its application toward the carbonylative Sonogashira reactions. The various catalyst characterization techniques revealed the successful grafting of APTES moiety on the K10 clay surface through covalent bonding and Pd with the NH2 groups of APTES@K10 through co-ordinate bonding. The immobilized catalyst was successively applied for copper and phosphine free carbonylative Sonogashira reaction of aryl and hetero aryl iodides with terminal alkynes. To our delight, the electron withdrawing aryl halides can be efficiently utilized as an electrophiles giving higher selectivity toward carbonylated products. Moreover, dibenzoylmethane which is a potential synthetic intermediate in organic transformation has been also synthesized using this protocol. Recovery of catalyst by simple filtration and its reuse up to four consecutive cycles ensure the robustness of present catalytic protocol.
Aluminum-catalyzed asymmetric alkylations of pyridyl-substituted alkynyl ketones with dialkylzinc reagents
Friel, Donna K.,Snapper, Marc L.,Hoveyda, Amir H.
supporting information; experimental part, p. 9942 - 9951 (2009/02/04)
Alkylations of pyridyl-substituted ynones with Et2Zn and Me 2Zn, promoted by amino acid-based chiral ligands in the presence of Al-based alkoxides, afford tertiary propargyl alcohols efficiently in 57% to >98% ee. Two easily accessib
