13343-78-7Relevant articles and documents
One-pot synthesis of α,β-unsaturated ketones through sequential alkyne dimerization/hydration reactions using the Hoveyda-Grubbs catalyst
?ztürk, Bengi ?zgün,?ehito?lu, Solmaz Karabulut,A?kun, Mina,Sar?aslan, Begüm,Tunal?, Zeynep
supporting information, p. 16689 - 16695 (2021/09/27)
Herein we report a sequential one-pot alkyne dimerization/hydration protocol for the regioselective synthesis of α,β-unsaturated ketones in quantitative yields. The alkyne dimerization reactions of terminal arylacetylenes proceeded with high regioselectivity in the presence of the Hoveyda-Grubbs 2nd generation catalyst (1 mol%) and tricyclohexylphosphine (4 mol%). The hydration reactions ofin situformed 1-aryl-3-en-1-ynes proceeded very rapidly in the presence of CCl3COOH/p-TsOH·H2O, yielding the corresponding unsaturated ketones within 15 minutes in quantitative yields. Different arylacetylene derivatives were converted to the corresponding α,β-unsaturated ketones in quantitative yields (94-95%) using sequential one-pot alkyne dimerization/hydration reactions.
Calix[4]trap: A Bioinspired Host Equipped with Dual Selection Mechanisms
Xu, Zhenchuang,Fang, Nie,Zhao, Yanchuan
supporting information, p. 3162 - 3168 (2021/03/08)
Regulation of recognition events evolving in time and space is vital for living organisms. During evolution, organisms have developed distinct and orthogonal mechanisms to achieve selective recognition, avoiding mutual interference. Although the merging of multiple selection mechanisms into a single artificial host may lead to a more adaptable recognition system with unparalleled selectivity, successful implementation of this strategy is rare. Inspired by the intriguing structures and recognition properties of two well-known biological ion binders - valinomycin and K+ channels - we herein report a series of hosts equipped with dual guest selection mechanisms. These hosts simultaneously possess a preorganized binding cavity and a confined ion translocation tunnel, which are crucial to the record-setting K+/Na+ selectivity and versatile capabilities to discriminate against a wide range of ion pairs, such as K+/Rb+, K+/Ba2+, and Rb+/Cs+. Mechanistic studies verify that the host's portal is capable of discriminating cations by their size, enabling varied ion uptake rates. The confined tunnel bearing consecutive binding sites promotes complete desolvation of ions during their inclusion into the buried cavity, mimicking the ion translocation within ion channels. Our results demonstrate that the capability to manipulate guest recognition both in equilibrium and out-of-equilibrium states allows the host to effectively discriminate diverse guests via distinct mechanisms. The strategy to merge orthogonal selection mechanisms paves a new avenue to creating more robust hosts that may function in complex biological environments where many recognition events occur concurrently.
Variation on the π-Acceptor Ligand within a RhI?N-Heterocyclic Carbene Framework: Divergent Catalytic Outcomes for Phenylacetylene-Methanol Transformations
Galiana-Cameo, María,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.,Di Giuseppe, Andrea,Castarlenas, Ricardo
, p. 2947 - 2957 (2021/07/16)
A series of neutral and cationic rhodium complexes bearing IPr {IPr=1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-carbene} and π-acceptor ligands are reported. Cationic species [Rh(η4-cod)(IPr)(NCCH3)]+ and [Rh(CO)(IPr)(L)2]+ (L=pyridine, CH3CN) were obtained by chlorido abstraction in suitable complexes, whereas the cod-CO derivative [Rh(η4-cod)(IPr)(CO)]+ was formed by the carbonylation of [Rh(η4-cod)(IPr)(NCCH3)]+. Alternatively, neutral derivatives of type RhCl(IPr)(L)2 {L=tBuNC or P(OMe)3} can be accessed from [Rh(μ-Cl)(η2-coe)(IPr)]2. In addition, the mononuclear species Rh(CN)(η4-cod)(IPr) was prepared by cyanide-chlorido anion exchange, which after carbonylation afforded the unusual trinuclear compound [Rh{1κC,2κN-(CN)}(CO)(IPr)]3. Divergent catalytic outcomes in the phenylacetylene-methanol transformations have been observed. Thus, enol ethers, arisen from hydroalkoxylation of the alkyne, were obtained with neutral Rh?CO catalyst precursors whereas dienol ethers were formed with cationic catalysts. Variable amounts of alkyne dimerization, cyclotrimerization or polymerization products were obtained in the absence of a strong π-acceptor ligand on the catalyst.
