Sulfur-containing molecules such as thioethers are commonly found in chemical biology, organic synthesis, and materials chemistry. While many reliable methods have been developed for preparing these ...compounds, harsh reaction conditions are usually required in the traditional methods. The transition metals have been applied in this field, and the palladium-catalyzed coupling of thiols with aryl halides and pseudo halides is one of the most important methods in the synthesis of thioethers. Other metals have also been used for the same purpose. Here, we summarize recent efforts in metal-catalyzed C-S bond cross-coupling reactions, focusing especially on the coupling of thiols with aryl- and vinyl halides based on different metals.
The recent decade evidenced a significant development in the construction of the C−S bond. The journey began with transitional‐metal catalysis and reached sustainable catalysis via oxidant, photo, ...and electro catalyzed methods. A variety of catalytic systems have been explored for the C−S bond formation using a variety of sulfur precursors. This personal account provides an inclusive discussion of these developed methods in terms of reactivity, sustainability and productivity.
This personal account provides an inclusive discussion about C−S constructions and the journey from transitional‐metal catalysis to sustainable catalysis via oxidant, photo and electro catalyzed methods.
A first visible‐light photoredox‐catalyzed thioacetalization of aldehydes under metal‐free and solvent‐free conditions is described. Under blue LED irradiation, a reactive thiyl radical was initially ...generated through single‐electron oxidation of thiol, which subsequently reacted with aldehydes to afford dithioacetals following a radical mechanism. The reaction proceeded under ambient conditions, and a wide range of acyclic and cyclic dithioacetal derivatives were afforded in good to excellent yields.
A molecular information ratchet SERRELI, Viviana; LEE, Chin-Fa; KAY, Euan R ...
Nature,
02/2007, Letnik:
445, Številka:
7127
Journal Article
Recenzirano
Motor proteins and other biological machines are highly efficient at converting energy into directed motion and driving chemical systems away from thermodynamic equilibrium. But even though these ...biological structures have inspired the design of many molecules that mimic aspects of their behaviour, artificial nanomachine systems operate almost exclusively by moving towards thermodynamic equilibrium, not away from it. Here we show that information about the location of a macrocycle in a rotaxane-a molecular ring threaded onto a molecular axle-can be used, on the input of light energy, to alter the kinetics of the shuttling of the macrocycle between two compartments on the axle. For an ensemble of such molecular machines, the macrocycle distribution is directionally driven away from its equilibrium value without ever changing the relative binding affinities of the ring for the different parts of the axle. The selective transport of particles between two compartments by brownian motion in this way bears similarities to the hypothetical task performed without an energy input by a 'demon' in Maxwell's famous thought experiment. Our observations demonstrate that synthetic molecular machines can operate by an information ratchet mechanism, in which knowledge of a particle's position is used to control its transport away from equilibrium.
In synthetic chemistry, the protection of aldehydes and ketones is crucial during multistep synthesis of complex molecules. Organic chemists have paid substantial attention to the synthesis of ...1,3‐oxathiolanes and 1,3‐oxathianes because of their considerable stability under acidic conditions and ease of removal of protecting groups. In this paper, we report the mild and efficient oxathiacetalization of aldehydes with 2‐mercaptoethanol and 3‐mercaptopropan‐1‐ol through visible‐light‐promoted eosin‐Y catalyzed C–S and C–O bond formation at ambient temperature under metal‐free conditions. This catalytic system also affords oxathiacetalization of ketones through photoredox catalysis.
A visible‐light‐promoted oxathiacetalization of aldehydes and ketones with 2‐mercaptoethanol and 3‐mercaptopropan‐1‐ol in the presence of eosin Y as catalyst is described leading to the formation of 1,3‐oxathiolanes and 1,3‐oxathianes at ambient temperature and under metal‐free conditions. The solvent is playing vital role in the protection of carbonyl compounds with mercaptoalcohol.
A combination of CuI with oxalic diamide is a powerful catalytic system for cross-coupling reaction of thiols with aryl bromides and chlorides. It is important to note that unactivated aryl chorides ...are coupled smoothly with aryl- and alkyl thiols to give the corresponding thioethers in good to excellent yields for the first time.
The clustered regularly interspaced short palindromic repeats (CRISPR)‐associated protein 9 (CRISPR/Cas9) is an efficient and precise gene‐editing technology that offers a versatile solution for ...establishing treatments directed at genetic diseases. Currently, CRISPR/Cas9 delivery into cells relies primarily on viral vectors, which suffer from limitations in packaging capacity and safety concerns. These issues with a nonviral delivery strategy are addressed, where Cas9•sgRNA ribonucleoprotein (RNP) complexes can be encapsulated into supramolecular nanoparticles (SMNP) to form RNP⊂SMNPs, which can then be delivered into targeted cells via supramolecular nanosubstrate‐mediated delivery. Utilizing the U87 glioblastoma cell line as a model system, a variety of parameters for cellular‐uptake of the RNP‐laden nanoparticles are examined. Dose‐ and time‐dependent CRISPR/Cas9‐mediated gene disruption is further examined in a green fluorescent protein (GFP)‐expressing U87 cell line (GFP‐U87). The utility of an optimized SMNP formulation in co‐delivering Cas9 protein and two sgRNAs that target deletion of exons 45–55 (708 kb) of the dystrophin gene is demonstrated. Mutations in this region lead to Duchenne muscular dystrophy, a severe genetic muscle wasting disease. Efficient delivery of these gene deletion cargoes is observed in a human cardiomyocyte cell line (AC16), induced pluripotent stem cells, and mesenchymal stem cells.
Supramolecular nanosubstrate‐mediated delivery facilitates intracellular entry of Cas9 ribonucleoprotein into target cells. Local enrichment of supramolecular nanoparticles from the surrounding medium onto nanowires via molecular recognition enables highly efficient clustered regularly interspaced short palindromic repeats‐associated protein 9 (CRISPR/Cas9) gene disruption and deletion. This platform offers a general clinical therapeutic solution for genetic diseases, such as Duchenne muscular dystrophy.
The synthesis of vinyl sulfides through the coupling reaction of thiols with vinyl iodides, bromides, and chlorides is described. The thiols can couple with aryl iodides in the presence of only 0.5 ...mol % Cu(2)O without the need for an ancillary ligand. In the presence of 5 mol % of Cu(2)O and 10 mol % 1,10-phenanthroline as the ligand, the more challenging alkyl vinyl bromides can also be coupled with thiols, giving the vinyl sulfides in good to excellent yields.
The preparation of thioesters through the iron-catalyzed coupling reaction of thiols with aldehydes is described. The reactions were carried out by using tert-butyl hydroperoxide (TBHP) as an oxidant ...and water as a solvent in most cases. This system is compatible with a variety of functional groups.
