Gold‐Catalyzed Fluorination–Hydration: Synthesis of α‐Fluorobenzofuranones from 2‐Alkynylphenol Derivatives

The Au^I‐catalyzed fluorination–hydration of 2‐alkynylphenol derivatives in the presence of Selectfluor [1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo‐[2.2.2]octane bis(tetrafluoroborate)] has been developed. This method provides straightforward access to α‐fluorobenzofuranones with the construction of C?O, C=O, and C?F bonds in a single step on the basis of an Au^I/Au^III redox catalytic cycle. Several control experiments, including the asymmetric variant of this reaction, were also conducted to gain insight into the reaction mechanism.     

Intermolecular Stetter reaction of aromatic aldehydes with (E)-(2-nitrovinyl)cyclohexane induced by N-heterocyclic carbene and thiourea

Intermolecular Stetter reaction of aromatic aldehydes with (E)-(2-nitrovinyl)cyclohexane catalyzed by thiazolium A has been developed. The reaction rate and efficiency are profoundly impacted by the presence of thiourea B. The reaction affords moderate to good yields of the Stetter product. Some factors influencing yield were discussed.     

Gold(I)/Chiral Brønsted Acid Catalyzed Enantioselective Hydroamination–Hydroarylation of Alkynes: The Effect of a Remote Hydroxyl Group on the Reactivity and Enantioselectivity

The catalytic enantioselective hydroamination–hydroarylation of alkynes under the catalysis of (R₃P)AuMe/(S)‐3,3′‐bis(2,4,6‐triisopropylphenyl)‐1,1′‐binaphthyl‐2,2′‐diyl hydrogenphosphate ((S)‐TRIP) is reported. The alkyne was reacted with a range of pyrrole‐based aromatic amines to give pyrrole‐embedded aza‐heterocyclic scaffolds bearing a quaternary carbon center. The presence of a hydroxyl group in the alkyne tether turned out to be very crucial for obtaining products in high yields and enantioselectivities. The mechanism of enantioinduction was established by carefully performing experimental and computational studies.     

Highly Efficient Dehydrogenative Coupling of Hydrosilanes with Amines or Amides Using Supported Gold Nanoparticles

Hydroxyapatite‐supported gold nanoparticles (Au/HAP) can act as a highly active and reusable catalyst for the coupling of hydrosilanes with amines under mild conditions. Various silylamines can be selectively obtained from diverse combinations of equimolar amounts of hydrosilanes with amines including less reactive bulky hydrosilanes. This study also highlights the applicability of Au/HAP to the selective synthesis of silylamides through the coupling of hydrosilanes with amides, demonstrating the first example of an efficient heterogeneous catalyst. Moreover, Au/HAP shows high reusability and applicability for gram‐scale synthesis.     

On Copper(I) Fluorides,the Cuprophilic Interaction,the Preparation of Copper Nitride at Room Temperature,and the Formation Mechanism at Elevated Temperatures

Our attempts to synthesize the hitherto unknown binary copper(I) fluoride have led to first successes and a serendipitious result: By conproportionation of elemental copper and copper(II) fluoride in anhydrous liquid ammonia, two copper(I) fluorides were obtained as simple NH₃ complexes. One of them presents an example of ligand‐unsupported “cuprophilic” interactions in an infinite [Cu₂(NH₃)₄]²⁺ chain with alternating Cu–Cu distances. We discovered that both copper(I) fluorides can easily be converted into Cu₃N at room temperature, just by applying a vacuum. Additionally, we investigated the formation mechanism of the classical synthesis route of Cu₃N that starts with CuF₂ and flowing NH₃ in the temperature range between ambient and 290 °C by means of thermal analysis and in situ neutron diffraction. The reaction proceeds at elevated temperatures through the formation of a blue and amorphous ammoniate Cu(NH₃)₂F₂, the reformation of CuF₂, and finally the redox reaction to form Cu₃N.     

Highly Efficient Copper(II) Ion Sorbents Obtained by Calcium Carbonate Mineralization on Functionalized Cross‐Linked Copolymers

A new type of Cu^II ion sorbents is presented. These are obtained by CaCO₃ mineralization from supersaturated solutions on gel‐like cross‐linked polymeric beads as insoluble templates. A divinylbenzene–ethylacrylate–acrylonitrile cross‐linked copolymer functionalized with weakly acidic, basic, or amphoteric functional groups has been used, as well as different initial inorganic concentrations and addition procedures for CaCO₃ crystal growth. The morphology of the new composites was investigated by SEM and compared to that of the unmodified beads, and the polymorph content was established by X‐ray diffraction. The beads, before and after CaCO₃ mineralization, were tested as sorbents for Cu^II ions. The newly formed patterns on the bead surface after Cu^II sorption were observed by SEM, and the elemental distribution on the composites and the chemical structure of crystals after interaction with Cu^II were investigated by EDAX elemental mapping and by FTIR‐ATR spectroscopy, respectively. The sorption capacity increased significantly after CaCO₃ crystals growth on the weak anionic bead surface (up to 1041.5 mg Cu^II/g sample) compared to that of unmodified beads (491.5 mg Cu^II/g sample).     

Alkyne Difunctionalization by Dual Gold/Photoredox Catalysis

Highly selective tandem nucleophilic addition/cross‐coupling reactions of alkynes have been developed using visible‐light‐promoted dual gold/photoredox catalysis. The simultaneous oxidation of Au^I and coordination of the coupling partner by photo‐generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross‐coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer–Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible‐light activation.     

Gold‐Catalyzed Tandem Cycloisomerization–Halogenation of Chiral Homopropargyl Sulfonamides

Two new gold‐catalyzed tandem cycloisomerization–halogenation reactions of chiral homopropargyl sulfonamides have been developed. Various enantioenriched 3,3‐diiodopyrrolidin‐2‐ols and 3‐fluoropyrrolidin‐2‐ols were obtained in moderate‐to‐good yields with excellent enantio‐ and diastereoselectivity.     

Regioselective Alkylative Carboxylation of Allenamides with Carbon Dioxide and Dialkylzinc Reagents Catalyzed by an N‐Heterocyclic Carbene–Copper Complex

The alkylative carboxylation of allenamide catalyzed by an N‐heterocyclic carbene (NHC)–copper(I) complex [(IPr)CuCl] with CO₂ and dialkylzinc reagents was investigated. The reaction of allenamides with dialkylzinc reagents (1.5 equiv) and CO₂ (1 atm.) proceeded smoothly in the presence of a catalytic quantity of [(IPr)CuCl] to afford (Z)‐α,β‐dehydro‐β‐amino acid esters in good yields. The reaction is regioselective, with the alkyl group introduced onto the less hindered γ‐carbon, and the carboxyl group introduced onto the β‐carbon atom of the allenamides. The first step of the reaction was alkylative zincation of the allenamides to give an alkenylzinc intermediate followed by nucleophilic addition to CO₂. A variety of cyclic and acyclic allenamides were found to be applicable to this transformation. Dialkylzinc reagents bearing β‐hydrogen atoms, such as Et₂Zn or Bu₂Zn, also gave the corresponding alkylative carboxylation products without β‐hydride elimination. The present methodology provides an easy route to alkyl‐substituted α,β‐dehydro‐β‐amino acid ester derivatives under mild reaction conditions with high regio‐ and stereoselectivtiy.     

MOEPGA: A novel method to detect protein complexes in yeast protein–protein interaction networks based on MultiObjective Evolutionary Programming Genetic Algorithm

The identification of protein complexes in protein–protein interaction (PPI) networks has greatly advanced our understanding of biological organisms. Existing computational methods to detect protein complexes are usually based on specific network topological properties of PPI networks. However, due to the inherent complexity of the network structures, the identification of protein complexes may not be fully addressed by using single network topological property. In this study, we propose a novel MultiObjective Evolutionary Programming Genetic Algorithm (MOEPGA) which integrates multiple network topological features to detect biologically meaningful protein complexes. Our approach first systematically analyzes the multiobjective problem in terms of identifying protein complexes from PPI networks, and then constructs the objective function of the iterative algorithm based on three common topological properties of protein complexes from the benchmark dataset, finally we describe our algorithm, which mainly consists of three steps, population initialization, subgraph mutation and subgraph selection operation. To show the utility of our method, we compared MOEPGA with several state-of-the-art algorithms on two yeast PPI datasets. The experiment results demonstrate that the proposed method can not only find more protein complexes but also achieve higher accuracy in terms of fscore. Moreover, our approach can cover a certain number of proteins in the input PPI network in terms of the normalized clustering score. Taken together, our method can serve as a powerful framework to detect protein complexes in yeast PPI networks, thereby facilitating the identification of the underlying biological functions.