Recyclable Heterogeneous Supported Copper-Catalyzed Coupling of Thiols with Aryl Halides: Base-Controlled Differential Arylthiolation of Bromoiodobenzenes
作者:Sukalyan Bhadra、Bojja Sreedhar、Brindaban C. Ranu
DOI:10.1002/adsc.200900358
日期:2009.10
Alumina-supported copper sulfate efficiently catalyzes the S-arylation of aromatic, heteroaromatic and aliphatic thiols with aryl as well as heteroaryl halides underaerobic, ligand-freeconditions. This protocol provides an easy access to a variety of thioethers as well as unsymmetrical bis-thioethers by base-controlled differential coupling of thiols with iodo- and bromo-substituents in an aromatic
Organocatalytic asymmetric epoxidation and tandem epoxidation/Passerini reaction under eco-friendly reaction conditions
作者:Anna Maria Deobald、Arlene G. Corrêa、Daniel G. Rivera、Márcio Weber Paixão
DOI:10.1039/c2ob26247a
日期:——
An eco-friendly synthesis of highly functionalized epoxides and their incorporation into an organocatalytic multicomponent approach are reported. For this, a modified class of diarylprolinol silyl ethers was designed to enable high catalytic activity in an environmentally benign solvent system. The one-pot procedure showed great efficiency in promoting stereoselective multicomponent transformations in a tandem, ‘green’ fashion. Because of its non-residual, efficient and selective character, this synthetic design shows promise for large-scale applications in both diversity and target-oriented syntheses.
Syntheses of Aryl Thioethers <i>via</i> Aromatic Substitution of Aryl Halides at 0 to 25 °C
作者:Marina Tsuzaki、Shin Ando、Tadao Ishizuka
DOI:10.1248/cpb.c23-00232
日期:2023.7.1
In this study, we developed mild conditions for the synthesis of an aryl thioether via aromatic substitution using aryl halides, which is a process that has rarely been studied. Aromatic substrates such as arylfluoridesactivated with a halogen substituent are difficult to use for substitution reactions, but by using 18-crown-6-ether as an additive, these were successfully converted to their corresponding
A general rhodium-catalyzed cross-coupling reaction of thiols with aryl iodides
作者:Chih-Shin Lai、Hsin-Lun Kao、Yan-Jhang Wang、Chin-Fa Lee
DOI:10.1016/j.tetlet.2012.06.054
日期:2012.8
The general procedure for the rhodium-catalyzed cross-coupling of thiols with aryl iodides is described. The catalytic system consists of 5 mol % of [RhCl(cod)](2) and 10 mol % of PPh3 as a ligand. A variety of aryl iodides reacted with thiols, giving aryl thioethers in good to excellent yields. It is important to note that the deactivated aryl iodides such as 4-iodoanisole is worked smoothly to provide the corresponding aryl thioethers in excellent yields. Functional groups such as free-amines, chloro, are all tolerated under the employed reaction conditions. (C) 2012 Elsevier Ltd. All rights reserved.
Enhanced Aggregation of Derivatized Tolan Surfactants through Donor−Acceptor Interactions at the Air−Water Interface and in Langmuir−Blodgett Films
作者:Catie Weiss Farahat、Thomas L. Penner、Abraham Ulman、David G. Whitten
DOI:10.1021/jp960579g
日期:1996.1.1
Control of aggregation behavior of derivatized surfactants by moderately polar functional groups as well as the role of charge-transfer interactions governing photophysical phenomena was studied using surfactants incorporating the diphenylacetylene (tolan) chromophore (TFAs) modified with either a sulfone or an ether group (sTA or oTA, respectively). H aggregation is prevalent in these systems as monitored by the spectral shifts of absorption and emission. Packing of surfactants and aggregation were found to be strongly influenced by the presence of bivalent metal cations, Cd2+, in the subphase, as demonstrated by molecular area and chain orientation measurements. The nature of the aggregates formed from sTA surfactants is directly affected by complexation of the acid headgroup; in contrast, the associated oTA chromophore aggregation is unaffected by subphase modifications, despite the altered packing of surfactant chains. The photophysical behavior of aggregated TFAs in monolayer systems was followed at the air-water interface as well as with supported films on quartz, and conclusions can be made of the surfactant arrangements' stability. A unique mixed aggregate was formed when both the ether- and sulfone-derivatized TFAs were incorporated into a single phosphatidylcholine molecule (mixed PC) and deposited as an LB film. This monolayer exhibits additional enhancement in aggregation properties attributed to donor-acceptor interactions between the tolan chromophores that are distinct from a statistically mixed LB sample prepared from a mixture of TFAs. The current results are viewed in terms of general principles governing aggregation for a family of chromophore-derivatized surfactants in LB film.