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We report here reactions of alkyl sulfides with benzynes thermally generated by the hexadehydro-Diels–Alder (HDDA) cycloisomerization. The initially produced 1,3-betaine (o-sulfonium/aryl carbanion) undergoes intramolecular proton transfer to generate a more stable S-aryl sulfur ylide. This can react in various manners, including engaging weak acids (HA) in the reaction medium. This can produce transient ion pairs ArSR2+A– that proceed to the products ArSR + RA. When cyclic sulfides are used, A– opens the ring and is incorporated into the product, an outcome that constitutes a versatile, three-component coupling process.

Visible-light (Blue LED lamp: hν=425±15 nm) photocatalyzed cross-coupling reactions of arylsulfonyl chloride with N-methylpyrrole, furan, thiophene and their derivatives have been achieved in moderate to good yields at room temperature. A plausible mechanism has been proposed for the reaction. The arylation takes place at the C–H bond (C2–H or C5–H) next to the heteroatom with a high regioselective manner! Moreover, arylsulfonyl chlorides utilized in this study are inexpensive, environmentally benign and relatively more stable towards temperature, moisture and air as compared to diazonium salts normally used as coupling partners in the previously reported methods for the synthesis of heterobiaryls through visible-light photocatalyzed conditions.

A novel approach to stereo controlled synthesis of cis–anti–cis fused triquinane is reported from readily accessible starting material, endo-tricyclo[5.2.1.02,6]deca-4,8-dien-4-bromo-3-one using Michael addition and radical cyclization reactions as key steps.

Enantiopure macrocyclic ligands were synthesized from (1R,2R)-(+)- and (1S,2S)-(−)-diphenylethylenediamine with 3,3'-methylenebis(5-(tert-butyl)-2-hydroxybenzaldehyde) and characterized. The chirality transfer and chiral inversion from ligand to copper(II) metal centre were studied using circular dichroism spectroscopy. The enantiopure binuclear copper(II) complexes (ΔΔ and ΛΛ) were used as catalysts for asymmetric nitroaldol reaction to generate β-nitroalcohol with 88% yield and 67% enantioselectivity. Copyright © 2015 John Wiley & Sons, Ltd.

A novel method is developed for the oxidation of thiols to the corresponding disulfides using 20 mol % haloacid (HBr or HI) in combination with dimethyl sulfoxide. A tentative mechanism is proposed for the oxidation. In addition to the advantages of cost-effectiveness, simple processes, and broad functional group tolerance, the exclusive formation of disulfides is the principle reward of this methodology while compared to known methods that further oxidize disulfides to S-oxides and other byproducts.

A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.

A new method is described for the oxidation of aliphatic- and aromatic disulfides containing electron-donating and electron-withdrawing groups to their corresponding thiosulfonates using oxone in combination with the MX (MX = KBr, KCl, NaBr and NaCl). No obvious electronic effects influence the yields of thiosulfonates. Avoiding the usage of toxic and unstable reagents, mild reaction conditions, short reaction times and cost-effectiveness are advantages of this methodology when likened to known methods for thiosulfonates syntheses.

A simple and novel protocol for the facile synthesis of complex angularly substituted tetracyclic and pentacyclic hybrid molecular frameworks containing a coumarinopyranpyrazole/pyrimidinedione and coumarin ring systems via a solid-state melt reaction (SSMR) through a domino process is developed.

A facile protocol is presented for the radical cyclization of halides to the corresponding bi- or tricyclic products.

A wide variety of nitriles react with sodium azide in the presence of a catalytic amount of cyanuric chloride or 2,4,6-trichloro-1,3,5-triazine (TCT) under mild reaction conditions to give the corresponding 5-substituted-1H-tetrazoles in good to excellent yields. Here, we used TCT as a source of hydrochloric acid to catalyze this cycloaddition reaction.

Polydentate ligands 1 and 2, which incorporate a terminal pyridyl moiety and an oxygen-rich oxalate dihydrizide/malonic dihydrizide spacer moiety, as well as their binuclear metal complexes [Cu212] and [Cu222], which adopt a 1:1 metal/ligand ratio, were synthesized and characterized. Both complexes were screened for their catalytic activity in the nitroaldol reaction, in which [Cu212] worked efficiently as catalyst for both substituted benzaldehyde and pyridinecarboxaldehyde, whereas [Cu222] is highly substrate specific and showed activity towards nitro-substituted aldehydes and pyridinecarboxaldehyde. Furthermore, as helicates are intrinsically chiral, the stereochemical architecture in the binuclear double-stranded Cu2 helicates as catalyst favored the diastereoselective syn product with nitroethane and nitropropane and their respective diastereoselectivities were determined by using 1H NMR spectroscopy.

Benzil derivatives such as diaryl 1,2-diketones are synthesized via the direct decarboxylative coupling reaction of aryl propiolic acids and their oxidation. The optimized conditions are that the reaction of aryl propiolic acids and aryl iodides is conducted at 140 °C for 6 h in the presence of 10 mol % CuI/Cu(OTf)2 and Cs2CO3, after which HI (aq) is added and further reacted. The method shows good functional group tolerance toward ester, aldehyde, cyano, and nitro groups. In addition, symmetrical diaryl 1,2-diketones are obtained from aryl iodides and propiolic acid in the presence of palladium and copper catalysts.

Nanorods of the title compound are synthesized from a mixture of Na(OAc), Ti(O-iPr)4, and hexadecyl-trimethyl-ammonium bromide in H2O and EtOH, followed by sintering of the obtained powder in air at 800 °C for 6 h.

The three-component reaction of aryl halides, sodium sulfide pentahydrate (Na2S⋅5 H2O), and propiolic acid in the presence of 2.5% bis(triphenylphosphine)palladium chloride [Pd(PPh3)2Cl2], 5% 1,4-bis(diphenylphosphino)butane (dppb) and 2 equivalents of 1,8-diazabicycloundec-7-ene (DBU) produces stereoselectively (Z)-3-arylthioacrylic acids in good yields. A study of the reaction pathway suggested that the CS bond formation between aryl halides and Na2S⋅5 H2O proceeded first, and the resulting intermediate reacted with propiolic acid to produce the desired product. In addition, when the resulting product was treated with acid, the respective thiochromenones were formed in good yields.

The process is completely regioselective and affords good to excellent yields of the desired pyrimidine system within a short time.

The coupling reaction of aryl alkynyl carboxylic acids and allyl acetates was carried out in the presence of nickel catalyst to produce the allyl alkynes in good yields. The optimized condition is that alkynyl carboxylic acid (1.0 equiv), allyl acetate (2.0 equiv), Ni(OAc)2·4H2O (10 mol %), AgOAc (10 mol %), and zinc (1.0 equiv) were reacted at 100 °C for 0.5 h. In addition, when allyl alcohol was employed instead of allyl acetate, the desired product was obtained in good yield. In addition, when the reaction was carried out in the presence of base such as DBU and Cs2CO3, the allene compounds were formed in good yield.

Optimized conditions are developed for the reaction of benzylic alcohols with trimethylsilyl cyanide.

Depending on the educt ratio and the amount of NH4OAc used, the condensation of 3-oxo-4-arylsulfonylbutanoates (I) with aromatic aldehydes yields densely functionalized cyclohexadienes (III) or pyridines (V).

Coupling of aryl iodides with propiolic acid is carried out under conditions A) at 50°C to produce the corresponding aryl alkynyl carboxylic acids.

The direct benzylation of 1,3-dicarbonyl compounds and 4-hydroxycoumarin with a wide variety of benzylic alcohols was achieved using trimethylsilyl trifluoromethanesulfonate as an efficient catalyst. The reaction proceeded under very mild conditions at room temperature providing the desired products in good to excellent yields.

A remarkable solvent preference for dehydrobromination to yield 10-Undecynoic acid (5) and 9-Undecynoic acid (6) is observed in the case of 10,11-dibromoundecanoic acid (1). Thus, 10-Undecenoic acid can be easily and quantitatively converted to 6 in PEG-400, while 5 is produced in PEG-200. 5 can also be obtained in non-polar solvents with PEG-200/400 as a phase transfer catalyst.

A two-step method for the construction of 2,6 disubstituted piperidines from an imine, 3-tri-n-butylstannyl-2-[(tri-n-butylstannyl)methyl] propene, and an aldehyde is described.

The rearrangements of epimeric endo - and exo - dicyclopentadienyl vinyl ethers in lithium perchlorate in reported and the mechanism of the rearrangement in confirmed using deuterium labelling.

A simple procedure for the C-alkylation of cyclic 1,3-diketones have been reported using Triton B as base in aqueous conditions.

Ritter reactions of alcohols and tert -butyl acetate with various nitriles were performed using iodine as a mild and effective catalyst under heating conditions to afford the corresponding amides in good to excellent yields.

The macrolide (+)-carbonolide B, the aglycon of the antibiotic carbomycin B, was synthesized via a convergent sequence. A key step of the approach is the union of aldehyde 6 with stannane 7 in the presence of MgBr 2 -OEt 2 as Lewis acid to afford the C 1 -C 9 fragment 26. This chelation-controlled process uses resident stereochemistry at C 4 to control stereochemistry at C 5 and C 6 . Elaboration of this fragment at both ends and incorporation of a C 11 -C 15 fragment (hydroxy enal 4) via esterification and intramolecular Emmons reaction was used to complete the synthesis

Solutions of o-iodoxybenzoic acid in dimethyl sulfoxide at 23 °C effect the highly selective oxidation of a number of 1,4-bisprimary or 1,4-primary-secondary diols to γ-lactols, permitting a conversion which could not previously be accomplished in one step.

Benzyl and naphthylmethyl vinyl ethers are inert in LPDE medium, whereas hetcroaromntic methyl vinyl ethers, viz., 2-furyl and 2-thicnylmelhyl vinyl ethers undergo formal [1,3] rearrangement in LPDE medium.

Nimonol was obtained from the fresh green whole leaves of Azadirachta indica and its structure has been reassigned on the basis of COSY, NOESY and 1 H NMR spectral data. 6-Acetylnimonol was identified as 6-acetoxyazadirone and dihydronimonol was shown to be identical to isomeldenin. The mp and 1 H NMR spectra of 6-acetylnimocinol were markedly different from those of 6-acetoxyazadirone showing that nimocinol and nimonol have different structures.

Two selective and mild aromatic annulation procedures are described for the synthesis of chiral substituted tetrahydronaphthalene derivatives from ( − )-menthone and ( + )-dihydrocarvone . © 1997 Elsevier Science Ltd.

Lithium perchlorate/diethyl ether (LPDE) mediated rearrangement of α- and β-endo-dicyclopentadienyl vinyl ethers 5 and 6 resulted in the formation of the aldehyde 8, indicating that the mechanism i...

A series of spiro-piperidine azetidinone were synthesized and evaluated as potential TRPV1 antagonists. An important issue of plasma stability was investigated and resolved. Further focused SAR study lead to the discovery of a potent antagonist with good oral pharmacokinetic profile in rat.

Nanocrystalline RuO2 was electrochemically lithiated using a 6Li-enriched negative electrode, and selected samples at various states of lithiation-delithiation were characterized ex situ by 6Li mag...

Phosphonate ligands, [RPO3]2-, are extremely versatile in the assembly of multi-tin and multi-copper architectures. We have used organostannoxane cores for supporting multi-ferrocene and multi-porphyrin peripheries. The copper-metalated multi-porphyrin compound is an excellent reagent for facile cleavage of DNA, even in the absence of a co-oxidant. Reaction oft-BuPO3H2 with Cu(C104)2. 6H2O in the presence of 2-pyridylpyrazole (2-Pypz) leads to the synthesis of a decanuclear copper (II) assembly.

An efficient new method to synthesize α-oxy N -acyl aminals and hemiaminals in a single step from readily synthesized N -acyl enamines has been developed using PhI(OAc) 2 as the oxidant. The reaction conditions are very mild and the products are obtained in good yields (65–92%). A possible mechanistic pathway is laid out.

( E )- N ′-(Ethoxymethylene)hydrazinecarboxylic acid methyl ester was synthesized in one step in good yield. This reagent was successfully applied to the one-pot synthesis of 4-substituted 2,4-dihydro-3 H -1,2,4-triazolin-3-ones from readily available primary alkyl and aryl amines. This reaction process is relatively mild and easy to carry out. It is especially useful for the formation of sterically hindered triazolinones, which are otherwise difficult to obtain via existing literature procedures. A possible mechanistic pathway for the transformation is outlined.