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We demonstrated the intermolecular [2+2+2] cycloaddition of aryl- and trifluoromethyl-substituted internal alkyne and ethyl cyano­formate, and succeeded in constructing the pyridine derivatives using the CoI2/dcype/Zn catalyst system. The reaction proceeded with a high regioselectivity, and two trifluoromethyl-substituted ethyl picolinate derivatives were obtained as a single regioisomer.

A syn-selective aza-aldol reaction of boron aza-enolates, generated from N-sulfonyl-1,2,3-triazoles and 9-BBN-H, is reported. It provides a sequential one-pot procedure for the stereoselective construction of 1,3-amino alcohols, having contiguous stereocenters, starting from terminal alkynes.

HfMnSb2 is synthesized by solid state reaction of stoichiometric mixtures of the elements (pressed pellet, evacuated quartz tube, 800 °C, 48 h).

Methods that can directly arylate pyridines have significant potential in synthetic chemistry. Herein, we present palladium-catalyzed C–H arylation of pyridines with aryl triflates that occurs regi...

In general, aromatic cores are stable owing to their resonance energies. Different from facile peripheral modifications of aromatic cores, transforming an aromatic core into a different skeleton is ambitious and has attracted only little attention as a general synthetic method. This personal account shows our journey to inventing transformations of dibenzothiophenes into triphenylenes, carbazoles, and spirocyclic diarylfluorenes and to establishing ‘aromatic metamorphosis’ as a useful and game-changing strategy in organic synthesis. 1 Introduction 2 Aromatic Metamorphosis 3 From Dibenzothiophenes to Triphenylenes 4 From Dibenzothiophenes to Carbazoles 5 From Dibenzothiophenes to Spirocyclic Tetraarylmethanes 6 Conclusion

Cross-dehydrogenative coupling (CDC) of two unfunctionalized heteroarenes has been recognized as an ideal transformation to synthesize privileged heterobiaryl scaffolds. However, regioselective activation and transformation of a specific set of two heterocyclic C–H bonds among other bonds have been extremely challenging. Thus, discovering a new controlling element to achieve regio-controlled and regio-divergent heterocyclic CDCs is considered crucial. In this Letter, the unprecedented use of organic halides as an oxidant to achieve the CDC reaction of pyridines and benzoxazoles with palladium catalyst is described. Moreover, the regioselectivity of the pyridine functionalization site can be controlled by the choice of organic halides.

Cp*CoIII-catalyzed C–H allylation of various aromatic C–H bonds using allyl alcohols as allylating reagents is described. Improved reaction conditions using fluorinated alcohol solvents afforded efficient directed C–H allylation of 6-arylpurines, benzamides, and a synthetically useful Weinreb amide with good functional group compatibility.

1-Alkoxybenzocyclobutenes undergo ring-opening hydrogenolysis with site-selective cleavage of the sterically hindered C(sp2)–C(sp3) bond on Pd/C.

A very simple and facile one-pot method for the synthesis of pyrimidine derivatives is presented. In this method, 2-aryl-pyrimidine derivatives were prepared by the reaction of ketene N,S-acetal 1 with commercially available aryl aldehydes by heating under solvent and catalyst-free conditions. The synthesized pyrimidine derivatives showed blue-green fluorescence in solid state.

Arylacetaldehydes were successfully synthesized by the anti-Markovnikov Wacker-type oxidation of vinylarenes using 1 atm O2 as a terminal oxidant under mild conditions. Electron-deficient alkenes, such as maleic anhydride and maleimides, were effective additives and would operate as ligands to stabilize the Pd(0) species during the reaction.

o-Alkylphenyl ketones undergo a C-C bond forming carboxylation reaction with CO2 simply upon irradiation with UV light or even solar light. The reaction presents a clean process exploiting light energy as the driving force for carboxylation of organic molecules with CO2.

Transformations of aromatic compounds into the corresponding amines, amides, and imides through carbon–hydrogen (C–H) bond functionalization represent one of the most step- and atom-economical methods for the synthesis of arylamine compounds. Because arylamines are privileged structures in materials- and biology-oriented functional molecules, the development of novel and efficient synthetic methods for aromatic C–H amination has received significant attention from a wide range of research fields including materials and pharmaceuticals. This review covers recent advances in catalytic aromatic C–H amination reactions. An array of recently developed new reactions are categorized by the nature of aromatic substrates: (1) 5-membered heteroarenes, (2) arenes having a nitrogen moiety in the molecule (intramolecular C–H amination), (3) arenes having a directing group, (4) simple arenes with excess amounts, and (5) simple arenes as the limiting reagents.

Aliphatic terminal alkenes react with pinacolborane at ambient temperature to afford dehydrogenative borylation compounds as the major product when iPr-Foxap is used as the ligand with cationic rhodium(I) in the presence of norbornene, which acts as the sacrificial hydrogen acceptor. The reaction is applied to the one-pot syntheses of aldehydes and homoallylic alcohols from aliphatic terminal alkenes.

The carbon–nitrogen bond of β-lactams is cleaved by palladium(0), and an alkene is intramolecularly inserted therein. The following reductive elimination produces nitrogen-containing benzo-fused tricycles in good to high yields.

An enamido group is site-selectively introduced at the C3-position of indoles by the rhodium(II)-catalyzed reaction with N-sulfonyl triazoles.

A thermal reaction of 4-(p-aminophenyl)-1-sulfonyl-1,2,3-triazoles forming benzoyl cyanides is reported. A carbene species thermally generated from the triazole by denitrogenation undergoes intramo...

Dibenzothiophene dioxides undergo nucleophilic aromatic substitution with anilines to form carbazoles in a single operation.

Treatment of the title cycloalkanols with Selectfluor and an substoichiometric amount of a silver salt leads to the γ- and β-fluoroalkyl ketones (II) and (IV), respectively.

N-Sulfonyl-1,2,3-triazoles react with thioesters in the presence of a rhodium(II) catalyst to produce β-sulfanyl enamides in a stereoselective manner. The reaction proceeds through generation of an α-imino rhodium carbene complex, nucleophilic addition of the sulfur atom of a thioester onto the carbenoid carbon atom, and subsequent intramolecular migration of the acyl group from the sulfur atom to the imino nitrogen atom. The method is successfully applied to a ring-expansion reaction of thiolactones, thus leading to the formation of sulfur-containing lactams.

We discovered that a reagent comprising a combination of PhBCl2 and nitriles was useful for syntheses of both 3-acylindoles and 1-(1H-indol-3-yl)alkylamine from indoles. The reaction proceeded selectively at the 3-position of indoles providing 3-acylindoles in moderate to high yields on treatment with the above reagent. Furthermore, the reaction provided the corresponding amine products in moderate to high yields after the intermediate imine was reduced by NaBH3CN. These reactions proceeded under mild conditions and are applicable to the formation of indoles functionalized at the 3-position.

Acylphosphonates are conveniently synthesized from aryl iodides by a palladium-catalyzed reaction with dialkyl phosphites under an atmospheric pressure of carbon monoxide. The reaction demonstrates the first example of the use of phosphorus nucleophiles in related metal-catalyzed carbonylation reactions.

α,β,γ,δ-Unsaturated imines are synthesized from N-sulfonyl-1,2,3-triazoles and allenes. Allenes are initially cyclopropanated by intermediate α-imino rhodium carbene complexes, and the resulting al...

3-Hydroxypiperidine scaffolds were enantioselectively constructed in an atom-economical way by sequential action of light and rhodium upon N-allylglyoxylamides. In a formal sense, the allylic CH bond was selectively cleaved and enantioselectively added across the ketonic carbonyl group with migration of the double bond (carbonyl-ene-type reaction).

Procedures are evaluated for the preparation of various thiazole structures either from triazole precursors (prepared from terminal alkynes and sulfonyl azides) or directly starting with their formation in a one-pot approach.

The direct C—H imidation of a variety of arenes and heteroarenes is possible with N-fluorobenzenesulfonamide in the presence of CuBr and 6,6′-dimethyl-2,2′-bipyridine.

The efficient method is applied in the synthesis of protein tyrosine phosphatase inhibitors of type (VI).

An efficient one-pot two-step procedure for asymmetric synthesis of piperidine-fused trans-cycloalkenes is reported. The method comprises the initial enantioselective installation of another cyclopropane ring onto methylenecyclopropanes and the subsequent thermal skeletal rearrangement in which the installed and inherent cyclopropane rings are both opened. A concerted mechanism is proposed for the latter thermal rearrangement reaction together with a closed transition state model.

A new secoiridoid glucoside, algiolide A (1), was isolated from the aerial parts of a Mongolian traditional herbal medicine Gentiana algida (Gentianaceae). The structure of 1 was elucidated on the basis of spectroscopic analysis and chemical conversion as well as calculations of NMR and ECD spectra. Algiolide A (1) has a novel skeleton consisting of fused α,β-unsaturated-δ-lactone and cyclopentene rings.

The reaction of ketene dithioacetals monoxides (II) with various phenols affords the corresponding 2-methylsulfanylbenzo[b]furan derivatives of type (III).

Relay actions of copper, rhodium, and gold formulate a one-pot multistep pathway, which directly gives 2,5-dihydropyrroles starting from terminal alkynes, sulfonyl azides, and propargylic alcohols.

A silica-supported caged trialkylphosphane is applied as efficient heterogeneous ligand in the Ir-catalyzed N- or O-atom directed C—H borylation of cyclopropanes and a few cyclobutanes to give cis-products.

A new pentacyclic indole alkaloid, kopsiyunnanine E, was isolated from Yunnan Kopsia arborea, and its structure, which was inferred from spectroscopic data, was established by a 16-step asymmetric total synthesis that proved that the natural alkaloid was not enantiomerically pure.

The synthesis of a wide variety of diarylamines from aryl sulfides and anilines is presented.

A new procedure for the stereoselective synthesis of syn α-amino β-oxy-ketones is reported.

Various aryl Grignard reagents undergo coupling not only with aryl and alkenyl iodides but also with bromides.

The reaction of ketene dithioacetal monoxides with phenols to synthesize multisubstituted furans is presented.

A regio- and stereo-controlled, one-pot amidoglycosylation of alcohols has been achieved using O-acetylated glycals, trichloroethoxysulfonamide, and iodosobenzene in the presence of a rhodium(II) catalyst. The reaction would proceed via stereoselective intermolecular aziridination of the glycal.

When a carbenoid species generated from a tosylhydrazone is reacted with a cyclobutanol in the presence of a chiral rhodium catalyst, a C–C single bond of the cyclobutanol is cleaved, and the carbenoid carbon is inserted therein to furnish a ring-expanded cyclopentanol in an enantioselective manner.

A new inhibitor named elatosides E (which was shown to affect the elevation of plasma glucose level by oral sugar tolerance test in rats) was isolated from the root cortex of Aralia elata SEEM. together with elatoside F. The structures of elatosides E and F were elucidated on the basis of chemical and physicochemical evidence. The hypoglycemic activities of oleanolic acid and nine oleanolic acid glycosides obtained from the root cortex of Aralia elata heve been examined, and some structure-activity relationships have been found.

Five triterpene oligoglycosides named escins-Ia, Ib, IIa, IIb, and IIIa were isolated from the seeds of Aesculus hippocastanum L. and their chemical structures were determined on the basis of chemical and physicochemical evidence. Escins-Ia, Ib, IIa, and IIb were found to exhibit inhibitory effect on ethanol absorption and hypoglycemic activity on oral glucose tolerance test in rats. Among them, escins-IIa and IIb showed the higher activities for both bioassays, while desacylescins-I and II had no activity.

Anodic oxidation of 23-hydroxyprotost-13(17)-ene fumished an unprecedented triterpenoidal skeleton, 17, 23-epoxyprotost-12-ene, while 23-acetoxyprotost-13(17)-ene was converted into 23-acetoxyprotost-13(17)-en-16-one.