Direct Dehydrogenative Access to Unsymmetrical Phenones.

The first non-directed dehydrogenative phenone coupling method of methylarenes with aromatic C-H bonds, displaying a large substrate scope, is herein reported. This reaction represents a far more direct atom- and step-efficient alternative to the classical Friedel-Crafts or Suzuki-Miyaura derived acylation reactions. The method can be carried out on a gram scale and was successfully applied to the synthesis of several Ketoprofen drug analogues.

TEMPO-mediated late stage photochemical hydroxylation of biaryl sulfonium salts.

The late stage photochemical hydroxylation of biaryl sulfonium salts was enabled with a TEMPO derivative as a simple oxygen source, in metal free conditions. The scope and mechanism of this exceptionally simple synthetic method, which constructs important arylated phenols from aromatic C-H bonds, are herein discussed.

Phosphine-Catalyzed Dearomative [3 + 2] Cycloaddition of Benzoxazoles with a Cyclopropenone.

The triphenylphosphine-catalyzed dearomative [3 + 2] cycloaddition of benzoxazoles with 1,2-diphenylcyclopropenone is herein described. The reaction scope, mechanism, and possible future applications of this rare organocatalyzed cycloaddition are herein discussed.

Electrochemical Dehydrogenative Acetalization Protection of Alcohols with Tetrahydrofuran.

A mild, facile, and environmentally friendly electrochemical protocol for the C(sp3)-H/O-H cross dehydrogenative coupling between various alcohols and tetrahydrofuran with H2 evolution is herein reported. This synthetic strategy does not require external oxidants nor catalysts. The broad functional group compatibility includes hydroxyl, halogens, olefins as well as an alkyne. Initial mechanistic investigations were conducted. The method provides a green and efficient hydroxyl group protection.

Photochemical (Hetero-)Arylation of Aryl Sulfonium Salts.

The construction of (hetero)biaryls, which are ubiquitous scaffolds among medical substances, functional materials, and agrochemicals, constitutes a key application of cross-coupling methods. However, these usually require multiple synthetic steps. Herein, we report a simple photoinduced and catalyst-free C-H/C-H (hetero)arylation cross-coupling through aryl thianthrenium salts, which are formed site-selectively by direct C-H functionalization. The key to this approach is the UV-light, which can disrupt the C-S bond to form thianthrene radical cations and aryl radicals.

Electro-Oxidative Selective Esterification of Methylarenes and Benzaldehydes.

A mild and green electro-oxidative protocol to construct aromatic esters from methylarenes and alcohols is herein reported. Importantly, the reaction is free of metals, chemical oxidants, bases, acids, and operates at room temperature. Moreover, the design of the electrolyte was found critical for the oxidation state and structure of the coupling products, a rarely documented effect. This electro-oxidative coupling process also displays exceptional tolerance of many fragile easily oxidized functional groups such as hydroxy, aldehyde, olefin, alkyne, as well as neighboring benzylic positions. The enantiomeric enrichment of some chiral alcohols is moreover preserved during this electro-oxidative coupling reaction, making it overall a promising synthetic tool.

Emerging unconventional organic solvents for C-H bond and related functionalization reactions.

Solvent engineering is an increasingly essential topic in the chemical sciences. In this context, some recently appeared unconventional solvents have shown their large potential in the field of C-H bond functionalization reactions. This review aims not only at recognizing and classifying a short selection of these emerging solvents, in particular halogenated ones, but also at providing a medium term perspective of the possibilities they will offer for synthetic method development.

Regioselective Oxidative Arylation of Fluorophenols.

A metal free and highly regioselective oxidative arylation reaction of fluorophenols is described. The relative position of the fluoride leaving group (i.e., ortho or para) controls the 1,2 or 1,4 nature of the arylated quinone product, lending versatility and generality to this oxidative, defluorinative, arylation concept.

Cu-Catalyzed Cross-Dehydrogenative ortho-Aminomethylation of Phenols.

A highly selective CuII -catalyzed cross-dehydrogenative ortho-aminomethylation of phenols with aniline derivatives is described. The corresponding C(sp2 )-C(sp3 ) coupling products were obtained in moderate to excellent yields under mild reaction conditions and with a broad substrate scope. A radical mechanism is proposed.

Gold(I)-Catalyzed Tandem Transformation with Diynes: Rapid Access to Linear Cyclopentenone-Fused Polycyclic Molecules.

An efficient and convenient synthesis of useful linear cyclopentenone-fused polycyclic compounds has been achieved through a novel gold(I)-catalyzed transformation of diynes. The method demonstrates high product yields and tolerates of a wide variety of important functional groups. Gold-vinylidene formation, methoxy group migration, and Nazarov-type cyclization are proposed to be the key steps in the reaction pathway. The synthetic utility of this method is demonstrated by converting the product to eight-membered-ring-fused compound.

An ESIPT based fluorescent probe for highly selective and ratiometric detection of periodate.

Periodate is widely used in organic and bioorganic chemistry, and also related to food and environmental safety. To best of our knowledge, there is no efficient tools reported for simultaneously quantifying periodate with high accuracy and discriminating periodate from other forms of iodine. We have synthesized, characterized and applied a first ratiometric fluorescent probe (PDS-2) for simultaneous monitoring of changes of periodate based on the excited-state intramolecular proton transfer mechanism. This PDS-2 based fluorescent technique may enable for a better understanding of periodate related biological and chemical processes. Also, it is an efficient tool for public health, food safety and environmental protection.

A review of experimental studies of hydrogen as a new therapeutic agent in emergency and critical care medicine.

Hydrogen is the most abundant chemical element in the Universe, but is seldom regarded as a therapeutic agent. Recent evidence has shown that hydrogen is a potent antioxidative, antiapoptotic and anti-inflammatory agent and so may have potential medical applications in cells, tissues and organs. There are several methods to administer hydrogen, such as inhalation of hydrogen gas, aerosol inhalation of a hydrogen-rich solution, drinking hydrogen dissolved in water, injecting hydrogen-rich saline (HRS) and taking a hydrogen bath. Drinking hydrogen solution (saline/pure water/other solutions saturated with hydrogen) may be more practical in daily life and more suitable for daily consumption. This review summarizes the findings of recent studies on the use of hydrogen in emergency and critical care medicine using different disease models.