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Overcoming the low reactivity of thioethers, a C(sp3)–H bond functionalization of thioethers with styrenes using TBHP and DBU involving a radical relay process in metal-free conditions with theoretical questions elaborated is described.

The synthesis of axially chiral compounds has attracted a great deal of attention in recent years. Herein, an efficient and economical synthetic route has been developed for 2-(3- carbamoylpyridin-2-yl) nicotinamide pyridine salts, axially chiral compounds. The starting material 1,10-phenanthroline is readily available. In this study, 2-(3-carbamoylpyridin-2-yl) nicotinamide pyridine salts are obtained in moderate to good yields. This protocol includes simple operations and has easy scalability. In addition, the axial chirality of the products is also preliminary studied.

High-nitrogen energetic compounds are widely used in military and civil fields. To cope with some special conditions, materials with high melting point and good heat resistance are required. Herein, synthetic approach of two TACOT-derived compounds with high heat resistance and strong insensitivity for friction has been optimized. Significantly, 100 g-scale of aza-TACOT(I) was prepared with a total yield of 80% and a purity of 99.9%. Meanwhile, aza-TACOT(II) was obtained with a purity of 98.9% under the optimized conditions. This practical method features scalable and simple operations. In addition, an acceptable mechanism was firstly proposed for the critical step.

A metal-free inactive C(sp

Direct oxidative coupling of inert C(sp

In the past three decades, rare-earth metal triflates including scandium triflate, yttrium triflate, and the lanthanide (La−Lu) triflate, were widely employed in the organic chemistry, such as cycl...

The C(sp3)–H bond is found widely in organic molecules. Recently, the functionalization of C(sp3)–H bonds has developed into a powerful tool for augmenting highly functionalized frameworks in organic synthesis. Based on the results obtained in our group, the present account mainly summarizes recent progress on the functionalization of C(sp3)–H bonds of aliphatic alcohols, ketones, alkyl nitriles, and ethers with styrene or cinnamic acid using tert-butyl hydroperoxide (TBHP) as a radical initiator.1 Introduction2 Oxidative Coupling of Styrenes with C(sp3)–H Bonds3 Decarboxylative Cross-Couplings of α,β-Unsaturated Carboxylic Acids with C(sp3)–H Bonds4 Conclusions

Abstract: A new type of NADH model compound, which has six asymmetric carbon centers, has been synthesized by an efficient and convenient method. We used NADH models combined with enzymes in the asymmetric reduction. It was the first time that dehydrogenase combined with NADH models instead of inorganic catalysts, such as MgCl2, was used in the asymmetric reduction. Furthermore, the experimental results showed that the new NADH model has the strongest fluorescence emission properties compared to previously reported models.

The synthesis of bioactive amides has been the pursuit of chemists. Herein secondary amides incorporated with an aldehyde group were first generated using aldehydes and secondary amines. Various (hetero)aryl aldehydes and even aliphatic aldehydes (40 examples) were converted into the desired products in moderate to excellent yields (up to 89%). A plausible mechanism involving a Cu(I/II/III) catalytic cycle combined with radical rearrangement was proposed and confirmed with four key intermediates detected by high-resolution mass spectrometry.

Rare-earth catalysis has become a hot topic in the field of catalytic organic reaction. Chain ethers mostly have lower reactivity and lower boiling points which limited their reaction scope. Herein, we found a rare-earth Y(OTf)3 can catalyze the coupling reaction of ethers especially chain ethers and thioethers with azaarenes. This protocol features simple operations, a broad substrate scope (31 examples), moderate to good yields (up to 85%), and atom economy.

Since carboxylic acid derivatives are commercially available, nontoxic, cheap, and normally stable to air and moisture, carboxylic acid derivatives are ideal reactants for synthetic strategy. In recent years, decarboxylative oxidative coupling reactions, which normally involve direct C-H bond activation, have attracted more and more interest from the synthetic community. Compared with conventional methods, this strategy is more environmentally friendly and step-economic. This review mainly focuses on recent advances of the decarboxylative oxidative coupling reaction.

A copper-catalyzed decarboxylative oxidative coupling of α,β-unsaturated carboxylic acids with non-cyclic ethers is developed. This method provides a new approach for C(sp3)–H bond functionalization of non-cyclic ethers. Mechanism study shows the reaction involves a radical process.

Direct difunctionalization of simple alkenes, the incorporation of two functional groups onto a carbon–carbon double bond, is of particular interest to the chemical community owing to its important applications in organic synthesis. Mechanistically, two types of reactions – metal-catalyzed nucleophilic difunctionalization and radical difunctionalization – dominate this research field. Radical difunctionalization is more appealing from a synthetic perspective than metal-catalyzed nucleophilic difunctionalization because it allows the conversion of simple alkenes into complex molecules in a rapid and convenient manner. Furthermore, radical difunctionalization allows addition to simple alkenes by various carbon-centered radicals and even heteroatom-centered radicals. This review gives an overview of intermolecular and intramolecular radical difunctionalization of simple alkenes, with an emphasis on the reaction patterns and mechanisms, as well as potential applications in synthetic chemistry.

A novel direct alkylation of thiophenes via bis-coupling with vinyl acetates has been developed. To the best of our knowledge, this represents the first report of the iron-catalysed coupling of two thiophenes with vinyl groups. Utilizing earth-abundant, inexpensive, and non-toxic iron catalysts, this methodology converts simple thiophenes to symmetrical dithienylethane derivatives under mild conditions in one step.

Rare-earth catalysis has become a hot topic in the field of catalytic organic reaction. Chain ethers mostly have lower reactivity and lower boiling points which limited their reaction scope. Herein, we found a rare-earth Y(OTf)

NAD(P)H and NAD+ have a significant role in biochemistry, and many NAD(P)H models received particular attention. Research in NADH models mainly focuses on asymmetric reduction and life sciences. Over the past few decades, a particularly large number of new chiral NAD(P)H models have appeared, and there have been significant developments in this area. We summarized advanced research in chiral NAD(P)H models in this paper. These models not only show very good performance in asymmetric reduction, but also have excellent fluorescence features. In addition, we present a discussion about some recent studies on the asymmetric reduction of NAD(P)H-dependent dehydrogenase, and we open a new door on research into NAD(P)H models. At last, some advances focused on the fluorescence phenomenon of some chiral NAD(P)H models have also been summarized. 1 Introduction 2 NAD(P)H Models with Symmetric Structure 2.1 Chiral NAD(P)H Models with C 1 Symmetry 2.2 Chiral NAD(P)H Models with C 2 Symmetry 2.3 Chiral NAD(P)H Models with C 3 Symmetry 3 Symmetric Reduction 3.1 Effect of the Substituents of Dihydronicotinamide 3.2 Effect of the C-4 Substituent of Dihydropyridine 3.3 Special Structures 3.4 Applying Dehydrogenase to Biocatalytic Asymmetric Reductions with NADPH 4 Fluorescence Properties 5 Conclusion

The first example of a metal-free unactivated C(sp3)–H bond functionalization of alkyl nitriles with terminal vinylarenes to provide γ-ketonitrile derivatives is described. This protocol features simple operations, a broad substrate scope, and atom and step economy. In addition, Cu-catalyzed C(sp3)–H bond functionalization of azodiisobutyronitrile (AIBN) and analogues with terminal vinylarenes to generate γ-ketonitriles was also studied. A preliminary free-radical pathway was confirmed by capturing an alkyl radical, and a conjugate system was found that can stabilize radical intermediates and be in favor of this transformation. Density functional theory (DFT) calculations also provide important evidence of the free-radical pathway.

It is of current development to construct high–performance energetic compounds by aggregation of energetic groups with dense arrangement. In this study, a hydrogen-free high-density energetic 3,4-bis(3-nitrofuroxan-4-yl)furoxan (BNTFO-I) was designed and synthesized in a simple, and straightforward manner. Its isomer, 3,4-bis(4-nitrofuroxan-3-yl)furoxan (BNTFO-IV), was also obtained by isomerization. The structures of BNTFO-I and BNTFO-IV were confirmed by single-crystal X-ray analysis for the first time. Surprisingly, BNTFO-I has a remarkable calculated crystal density of 1983 g cm−3 at 296 K, which is distinctly higher than BNTFO-IV (1.936 g cm−3, 296 K), and ranks highest among azole-based CNO compounds yet reported. It is noteworthy that BNTFO-I exhibits excellent calculated detonation properties (vD, 9867 m s−1, P, 45.0 GPa). The interesting configuration differences of BNTFO-I and BNTFO-IV provide insight into the design of new advanced energetic materials.

Studying NADH molecules is one of the most active areas in biomimetic research. It is important to design novel and efficient chiral NADH model molecules. Herein, a cage-like NADH model with multi-chiral centers was designed, and key intermediates have been synthesized. In this study, we found that pentafluorophenoxy group is an excellent leaving group for our synthetic route.

A novel copper/manganese cocatalyzed direct oxidative coupling of terminal vinylarenes with ketones via C(sp(3))-H bond functionalization following C-C bond formation has been developed using tert-butyl hydroperoxide as the radical initiator. Various ketones underwent a free-radical addition of terminal vinylarenes to give the corresponding 1,4-dicarbonyl products with excellent regioselectivity and efficiency through one step. A possible reaction mechanism has been proposed.

Transition-metal-catalyzed direct carbon–hydrogen bond functionalization has made significant advances in the field of carbon–hydrogen bond activation over the past decades. This methodology has the potential to be used in many different areas of chemistry; for example, it can provide an opportunity for the synthesis of various kinds of complex compounds. This account mainly focuses on recent advances in transition-metal-catalyzed direct sp3-carbon–hydrogen bond functionalization to form carbon–carbon bonds. 1 Introduction 2 Carbon–Carbon Bond Formation via Direct sp3-Carbon–Hydrogen Bond Functionalization 2.1 Coupling of sp3-Carbon–Hydrogen and sp-Carbon–Hydrogen Bonds 2.2 Coupling of sp3-Carbon–Hydrogen and sp2-Carbon–Hydrogen Bonds 2.3 Coupling of sp3-Carbon–Hydrogen and sp3-Carbon–Hydrogen Bonds 2.4 Coupling of sp3-Carbon–Hydrogen and C–X Bonds 3 Conclusion

A novel and concise method for the construction of γ-nitro ketones and 1,3-dinitro compounds with chemoselective acyl transfer has been presented under basic conditions via one-pot reactions. These reactions feature high atom- and step-economic possess, mild condition and simple operation for one-pot synthesis of aliphatic nitro compounds. This protocol provides the products in good yields. The possible reaction mechanism has also been proposed.

A new oxidation system (Na2S2O4/TBHP) to prepare pyridine derivatives has been developed by the oxidation of 1,4-dihydropyridine derivatives and polyhydroquinoline derivatives in good to excellent yields. The procedures of the reaction were green, convenient, mild and easy work-up.

Nickel-catalyzed functionalization of C(sp3)–H bonds adjacent to a nitrogen atom in amides through decarboxylative cross-coupling of α,β-unsaturated carboxylic acids is reported. A possible reaction mechanism is proposed that involves radical intermediate species.

C(sp3)–H Bonds are the most common structures in organic molecules. In recent years, the direct functionalization of C(sp3)–H bonds has attracted wide attention and made significant progress. This review mainly focuses on C(sp3)–H bond functionalization of alkanes with or without functional groups via radical processes reported since 2017. In particular, three methods of generating free radicals are discussed: the use of a radical initiator such as TBHP or DTBP; photocatalysis, and via 1,5-hydrogen atom transfer (1,5-HAT).1 Introduction2 C(sp3)–H Bond Functionalization of Alkanes3 C(sp3)–H Bond Functionalization of Alkanes with a Functional Group4 Conclusions

This review focuses on recent progress in organocatalytic and metal-mediated asymmetric [3 + 2] cycloadditions, including ‘click’ chemistry, asymmetric 1,3-dipolar and asymmetric non-1,3-dipolar [3 + 2] cycloadditions. The theoretical aspects and synthetic applications of these organocatalytic and metal-mediated asymmetric [3 + 2] cycloadditions are summarized. In addition, an understanding of the mechanistic details which lead to efficient stereoselectivity in organocatalytic and metal-mediated asymmetric [3 + 2] cycloadditions is provided. Most of the references reviewed in this paper are from 2007 upto now.

A FriedeleCrafts alkylation reaction of thiophenes with glyoxylate imine was developed to give a-aminoesters. In the presence of FeCl3$6H2O as the catalyst, various a-aminoesters were prepared with moderate to high yields (up to 95%) except for some special substrates.

Friedel–Crafts alkylation reactions of ethyl glyoxylate with various thiophenes to give the corresponding chiral secondary alcohols were demonstrated. The majority of these reactions proceeded with good enantioselectivities (up to 91 %) and satisfactory isolated yields. Notably, we found that 2-substituted thiophenes underwent the reaction more smoothly than unsubstituted and 3-substituted thiophenes.

A novel chiral nicotinamide adenine dinucleotide hydrogen (NADH) model with C 3 symmetry was designed and synthesized. Hydrogens at the C-4 position of all dihydropyridine rings in the inner part of the bowl could transfer to the substrate with powerful enantioselectivity. This novel C 3 symmetrical NADH model is capable of fluorescence emission at 455 nm when excited at 390 nm.

A novel palladium-catalyzed oxidative C-H functionalization protocol for the synthesis of (2-oxoindolin-3-ylidene)methyl acetates has been developed. In the presence of Pd(OAc)2 and PhI(OAc)2, a variety of N-arylpropiolamides underwent the C-H functionalization reaction with acids to afford the corresponding (E)-(2-oxoindolin-3-ylidene)methyl acetates selectively in moderate to excellent yields.

A new oxidation system (Na2S2O4/TBHP) to prepare pyridine derivatives has been developed by the oxidation of 1,4-dihydropyridine derivatives and polyhydroquinoline derivatives in good to excellent yields. The procedures of the reaction were green, convenient, mild and easy work-up.

A controlled new oxidant sulfate radical anion (SO4.–) was found and it can be easily prepared by mixing Na2S2O4 and TBHP with stirring. In this new metal-free oxidation system (Na2S2O4/TBHP), SO4.– can be used as a controllable oxidant to oxidize various aromatic alcohols to the corresponding aldehydes in good yields without any acid formation at room temperature. SO4.– was determined by a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) spin-trapping EPR method at room temperature on a Bruker E500 spectrometer and the results suggested that SO4.– was generated in this transformation.

A novel copper/manganese cocatalyzed direct oxidative coupling of terminal vinylarenes with ketones via C(sp3)–H bond functionalization following C–C bond formation has been developed using tert-butyl hydroperoxide as the radical initiator. Various ketones underwent a free-radical addition of terminal vinylarenes to give the corresponding 1,4-dicarbonyl products with excellent regioselectivity and efficiency through one step. A possible reaction mechanism has been proposed.

Nicotinamide adenine dinucleotide hydrogen (NADH) could play an important role in living systems and this has stimulated a great deal of interest in the fields of bioorganic and organic chemistry. A large number of NADH model compounds have been developed for studying stereoselective reduction. Herein, the factors involved in stereoselective reduction using NADH model compounds are discussed and the progress of research on coenzyme NADH model compounds is summarized. 1 Introduction 2 Factors of Stereoselective Reduction Using NADH Models 2.1 Effect of a Remote Sterically Demanding Side Chain 2.2 Effect of a Substituent at C-4 of the Dihydropyridine Ring 2.3 Effect of a Special Conformation 3 Conclusion

A novel and effective protocol for the synthesis of 2-substituted 3-halo-1 H-indoles by PdX 2 /CuX 2 -catalyzed annulations of 2-ethynylbenzeneamines has been developed. In the presence of PdX 2 and CuX 2 , the annulation reactions of a variety of 2-ethynylbenzeneamines were conducted in moderate to good yields. It is noteworthy that only N-acetyl-protected 2-ethynylbenzeneamines can undergo the reaction successfully.