RAFT Polymerization of S-Vinyl Sulfide Derivatives and Synthesis of Block Copolymers Having Two Distinct Optoelectronic Functionalities

Hydrothiolation of Triisopropylsilyl Acetylene Sulfur Pentafluoride - Charting the Chemical Space of β-SF5 Vinyl Sulfides

Recently, we suggested liquid and high-boiling TIPS-CC-SF5 (TASP) as a versatile reagent to access so far elusive SF5-containing building blocks by less specialized laboratories under bench-top conditions. The synthesis of non-aromatic SF5 building blocks generally requires on-site fluorination or pentafluorosulfanylation steps employing toxic and/or gaseous reagents. Herein, we underline the versatility of this reagent by reporting a benign bench-top protocol for the synthesis of Z-configured β-pentafluorosulfanylated vinyl sulfides in good to excellent yields (up to 99 %) with exclusive (Z)-diasteroselectivity and broad functional group tolerance. This method exploits an in-situ protodesilylation-hydrothiolation sequence. This so far uncharted class of compounds was characterized by means of NMR-spectroscopy as well as SC-XRD. Furthermore, we suggest the reaction to proceed via a kinetically controlled closed-shell reaction pathway, corroborated by in-silico experiments.

Gold-Catalyzed Intermolecular Alkyne Insertion into the N-S Bond in Sulfenamides

Gold-catalyzed reactions between sulfenamides and terminal alkynes proceeded via cis-insertion of alkynes into the N-S bond in sulfenamides, affording the corresponding β-sulfenylenamines in yields up to 90%. Mechanistic studies revealed that the reactions proceeded via nucleophilic attack of the sulfenamide nitrogen atom on the π-activated alkyne, followed by tosylate-assisted intermolecular transfer of the sulfenyl group.

Base-Promoted Synthesis of Vinyl Sulfides from Sulfonium Triflates

A new protocol has been developed for vinyl sulfide synthesis promoted by an alkoxy base under metal-free conditions. In this reaction, aryl and alkenyl sulfonium triflates with diverse functionalities are converted into vinyl sulfides with excellent reactivity. This transformation features mild and safe reaction conditions that avoid catalyst, transition metal, high-pressure gas, and high reaction temperature without compromising efficiency.

Threonine-Based Stimuli-Responsive Nanoparticles with Aggregation-Induced Emission-Type Fixed Cores for Detection of Amines in Aqueous Solutions

Stimuli-responsive polymeric nanoparticles (NPs) exhibit reversible changes in the dispersion or aggregation state in response to external stimuli. In this context, we designed and synthesized core-shell NPs with threonine-containing weak polyelectrolyte shells and fluorescent cross-linked cores, which are applicable for the detection of pH changes and amine compounds in aqueous solution. Stable and uniform NP(dTh) and NP(Fl), consisting of fluorescent symmetric diphenyl dithiophene (dTh) and diphenyl fluorene (Fl) cross-linked cores, were prepared by site-selective Suzuki coupling reactions in self-assembled block copolymer. NP(Fl) with the Fl unit in the core showed a high fluorescence intensity in different solvents, which is regarded as an aggregation-induced emission-type NP showing strong emission in aggregated states in the cross-linked core. Unimodal NPs were observed in water at different pH values, and the diameter of NP(Fl) changed from 122 (pH = 2) to 220 nm (pH = 11). Furthermore, pH-dependent changes of the fluorescence peak positions and intensities were detected, which may be due to the core aggregation derived from the deprotonation of the threonine-based shell fragment. Specific interactions between the threonine-based shell of NP(Fl) and amine compounds (triethylamine and p-phenylenediamine) resulted in fluorescence quenching, suggesting the feasibility of fluorescent amine detection.

Vinyl mercaptoethanol as a reactive monomer for the preparation of functional homo- and copolymers with (meth)acrylates

Vinyl mercaptoethanol is a scalable vinyl thioether monomer, which can readily be polymerized in a free radical process or by controlled methods. It tends to form alternating copolymers if copolymerized with acrylates and methacrylates.

Anthranilamide-protected vinylboronic acid: rational monomer design for improved polymerization/transformation ability providing access to conventionally inaccessible copolymers

We designed a vinyl-boronic-acid protected by anthranilamide as a “transformable” monomer in radical polymerization to synthesize conventionally inaccessible copolymers, such as poly(vinyl alcohol-co-styrene) and poly(ethylene-co-acrylate).

Polymers from S-vinyl monomers: reactivities and properties

This review summarises the work of several decades on the polymerisation of S-vinyl monomers, ranging from the early reports of suitable polymerisation techniques for these monomers to their recent renaissance in various applications.

Visible-light photocatalytic preparation of alkenyl thioethers from 1,2,3-thiadiazoles and Hantzsch esters: synthetic and mechanistic investigations

A visible-light-promoted S-alkylation of 1,2,3-thiadiazoles with C-radical precursors, 4-alkyl-1,4-dihydropyridines (DHPs), to produce alkenyl thioethers is disclosed.

Efficient labeling of organic molecules using 13C elemental carbon: universal access to 13C2-labeled synthetic building blocks, polymers and pharmaceuticals

Synthetic methodology enabled by ¹³C-elemental carbon is reported. Calcium carbide Ca¹³C₂ was applied to introduce a universal ¹³C₂ unit in the synthesis of labeled alkynes, O,S,N-vinyl derivatives, labeled polymers and ¹³C₂-pyridazine drug core.

Acetylene in Organic Synthesis: Recent Progress and New Uses

Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule.

Exploring the performance of nanostructured reagents with organic-group-defined morphology in cross-coupling reaction

The great impact of the nanoscale organization of reactive species on their performance in chemical transformations creates the possibility of fine-tuning of reaction parameters by modulating the nano-level properties. This methodology is extensively applied for the catalysts development whereas nanostructured reactants represent the practically unexplored area. Here we report the palladium- and copper-catalyzed cross-coupling reaction involving nano-structured nickel thiolate particles as reagents. On the basis of experimental findings we propose the cooperative effect of nano-level and molecular-level properties on their reactivity. The high degree of ordering, small particles size, and electron donating properties of the substituents favor the product formation. Reactant particles evolution in the reaction is visualized directly by dynamic liquid-phase electron microscopy including recording of video movies. Mechanism of the reaction in liquid phase is established using on-line mass spectrometry measurements. Together the findings provide new opportunities for organic chemical transformations design and for mechanistic studies.

Synthesis and Optoelectronic Properties of Block and Random Copolymers Containing Pendant Carbazole and (Di)phenylanthracene

Synthesis of novel block and random copolymers, containing a carbazole unit and (di)phenylanthracene moiety in the side chains, has been described in this paper. Block and random copolymers composed of 4-bromophenyl vinyl sulfide (BPVS) and N-vinylcarbazole (NVC) were initially prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. Then, anthracene-based groups were introduced on the bromophenyl unit in the carbazole-containing copolymers by Pd-catalyzed coupling to yield functional copolymers with additional (di)phenylanthracene units. The resulting copolymers, having two distinct electronic functionalities, exhibited characteristic fluorescence resonance energy transfer, as confirmed by UV-vis and fluorescence spectra.

General Synthesis of Alkenyl Sulfides by Palladium-Catalyzed Thioetherification of Alkenyl Halides and Tosylates

The cross-coupling reaction of alkenyl bromides with thiols catalyzed by palladium complexes derived from inexpensive dppf ligand is reported. These reactions occur under low catalyst loading and in high yields and display wide scope, including the coupling of bulky thiols and trisubstituted bromoolefins, and functional group tolerance. In addition, the thioetherification of less reactive chloroalkenes and, for the first time, alkenyl tosylates was accomplished using a catalyst generated from CyPF tBu alkylbisphosphine ligand.

Tacticity effects in side-chain photoluminescent polymers

A significant red shift (or blue shift) can be observed by increasing the degree of isotacticity (or syndiotacticity).

RAFT polymerization to form stimuli-responsive polymers

Stimuli-responsive polymers respond to a variety of external stimuli, which include optical, electrical, thermal, mechanical, redox, pH, chemical, environmental and biological signals. This paper is concerned with the process of forming such polymers by RAFT polymerization.

Facile synthesis, sequence-tuned thermoresponsive behaviours and reaction-induced reorganization of water-soluble keto-polymers

Water-soluble keto-polymers: facile synthesis in methanol on irradiation with visible light at 25 °C, sequence-tuned thermoresponsive behaviours and reaction-induced reorganization.