A synthetic strategy of a palladium-catalyzed cascade annulation reaction followed by aerial oxidation was designed to construct 6H-benzo[c]chromene scaffolds. Various 6H-benzo[c]chromenes were synthesized under mild conditions using easily accessible p-QMs and commercially available o-hydroxyarylboronic acids. One the chromenes has been ambiguously confirmed single-crystal XRD analysis. Interestingly, our could be transformed into valuable 6H-benzo[c]chromen-6-ones via oxidation.

A palladium catalyzed cascade reaction of 4-hydroxycoumarins and in situ generated arynes has been developed for the direct synthesis coumestans. This strategy proceeds via C-H bond activation/C-O C-C formations a single vessel. methodology affords moderate to good yields coumestans is tolerant variety functional groups including halide. The was applied natural product flemichapparin C.

Abstract A facile and efficient procedure for the ipso ‐hydroxylation of arylboronic acids to phenols in water was developed. series electron‐rich electron‐deficient were smoothly ‐hydroxylated with this protocol afford products excellent yields. Moreover, is amenable boronate esters. In most cases, phenolic obtained pure form without any chromatographic purification.

Synthesis of magnetically recoverable Ni nanoparticles supported reduced graphene oxide sheets as an efficient catalyst for the Sonogashira cross-coupling reaction.

A simple and straightforward method has been developed for the direct synthesis of unsymmetrical Z‐azo‐aryl compounds from p‐quinone methide (p‐QM) arylhydrazine. This reaction strategy is executed in air under basic conditions affords exclusively Z‐isomers good yields with a broad substrate scope. The stereochemistry our synthesized azo‐arenes confirmed by 2D‐NMR analyses.

A novel transition-metal-free direct synthesis of 3-substituted isocoumarin from 4-hydroxycoumarin and a benzyne precursor is developed. This synthetic strategy proceeds via C–O C–C bond cleavage as well formations in single reaction vessel by simple treatment with CsF the absence catalyst. methodology affords moderate to good yields isocoumarins tolerant variety functional groups including halide.

<italic>In situ</italic> synthesis of Pd nanoparticles on graphene nanosheets with simultaneous reduction alkene to alkane using hydrogen gas were utilized as efficient catalysts for the Suzuki cross-coupling reaction.

A transition-metal-free coupling reaction of aryne, DMSO, and activated alkyne for the synthesis 2-[( o-methylthio)aryloxy]-substituted dialkyl maleates is reported. This cascade process associated with several bond cleavage as well formation reactions in one pot. One our synthesized has been unambiguously established by single-crystal XRD studies. methodology allows preparation trisubstituted vinyl ethers excellent stereospecificity.

Arynes due to their transient nature leads remarkable and versatile applications in the synthetic world. Apparently, researchers have focused on construction of simple complex π-conjugated systems using arynes as reactive platform. In this regard, Kobayashi's aryne precursor has shown a great extent reactivity afforded significant advancement synthesis polycyclic aromatic with wide practical utility. This review emphasizes extensive utilization intermediates derivatives for different classes...

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSurfactant/I2/Water: An Efficient System for Deprotection of Oximes and Imines to Carbonyls under Neutral Conditions in WaterPranjal Gogoi, Parasa Hazarika, Dilip KonwarView Author Information Organic Chemistry Division, Regional Research Laboratory, Jorhat-785006, Assam, India %dkonwar @yahoo.co.ukCite this: J. Org. Chem. 2005, 70, 5, 1934–1936Publication Date (Web):January 29, 2005Publication History Received5 November 2004Published online29 January...

A new system, I2–KI–K2CO3–H2O, selectively oxidized alcohols to aldehydes and ketones under anaerobic condition in water at 90 °C with excellent yields. The process is green, mild inexpensive.

A simple, efficient, mild and green method has been developed for the synthesis of 3,4-dihydropyrimidin-2-ones employing dodecyl sulfonic acid as an excellent surfactant-type Brønsted catalyst in aqueous media at room temperature. The was shown to be equally effective 1,5-benzodiazepines under same reaction condition.

Daily vitamins: A mild, general, and highly stereoselective Pd0-catalyzed cascade to the triene system of hormone 1α,25-dihydroxyvitamin D3 six representative analogues is reported. The intramolecular cyclization an enol–triflate (lower fragment) followed in situ by Suzuki–Miyaura coupling with alkenyl boronic ester (upper fragment, also efficiently prepared coupling) equimolar amounts under protic conditions ideal for preparation small new vitamin D biological testing (see scheme).

The Cu(0) nanoparticle-rGO composites exhibit excellent catalytic activity for the synthesis of symmetrical biaryls from arylboronic acids under microwave irradiation.

A novel heterogeneous catalytic hydrogenation–hydrogenolysis strategy has been developed for the α-methylation of ketones via enaminones using DMF dimethyl acetal as carbon source. This provides a very convenient route to α-methylated variety without any base or oxidant.

A three-component cascade method has been developed for the direct synthesis of polysubstituted pyridines. This strategy provides a very convenient route to pyridines using variety β-bromo-α,β-unsaturated aldehydes, 1,3-diketones, and ammonium acetate without any additional catalyst or metal salt under mild conditions. β-ketoesters 4-hydroxycoumarin were also used instead 1,3-diketones diverse polycyclic One synthesized unambiguously established by single crystal XRD study. All pyridine...

A Pd(II)-catalyzed oxidative annulation reaction of 4-hydroxycoumarin and arylcarboxylic acid via double C-H bond activations has been accomplished for the synthesis bis-coumarins. This synthetic strategy provides a wide range structurally diversified bis-coumarins in moderate to good yields with variety functional group compatibility. Moreover, photophysical properties synthesized have evaluated, which reveals their interesting fluorescent properties.

Abstract Various 1,5‐benzodiazepine and quinoxaline derivatives have been synthesized in water with excellent yields using a catalytic amount of indium chloride at room temperature. This synthetic protocol is nontoxic, safe, environmentally benign.

A cascade synthetic strategy for the direct synthesis of 2-aroyl benzofurans from aryne precursors has been developed. This reaction proceeds via C-O and C-C bond cleavage as well formation in a single vessel. The methodology provides good yields tolerates variety functional groups. synthesized were further benzoylated at 3-positions one 2,3-diaroyl benzofuran structures was confirmed unambiguously by X-ray crystallography.