Themed collection HOT articles in Organic Chemistry Frontiers in 2016
Synthesis of a figure-eight azahelicene dimer with high emission and CPL properties
A bisbutadiyne bridged azahelicene dimer with a figure-eight shape, which exhibited both high fluorescence quantum yield and CPL properties, has been synthesized through the Glaser–Hay homo-coupling reaction with diethynylazahelicene.
Mechanism of selective C–H cyanation of 2-phenylpyridine with benzyl nitrile catalyzed by CuBr: a DFT investigation
The mechanism of C–H cyanation of 2-phenylpyridine with 2-phenylacetonitrile catalyzed by the CuBr catalyst was elaborated based on DFT calculations.
New reactivity of ethynyl benziodoxolone: modulating iron-catalyzed dehydration of propargyl alcohols
This is the first example of using only a catalytic amount of silyl-EBX in a dehydration reaction since its discovery. Preliminary mechanistic studies ruled out the radical pathways and supported an E1 process.
The stability and reactivity of tri-, di-, and monofluoromethyl/methoxy/methylthio groups on arenes under acidic and basic conditions
The stability and reactivity of tri-, di- and monofluoromethyl groups under acidic and basic conditions are described.
Direct observation and characterisation of 3-azido-2H-azirines: postulated, but highly elusive intermediates
The title compounds, including the parent 3-azido-2H-azirine, were generated by low-temperature photolysis of the corresponding 1,1-diazidoethenes, and characterised not only by trapping reactions, but also by direct detection using NMR and in situ IR spectroscopy.
Copper-mediated annulation of 2-(1-arylvinyl) anilines and aryl nitrosos towards 2,3-diaryl-2H-indazoles
A copper-mediated annulation of 2-(1-substituted vinyl)anilines and aryl nitrosos is developed, giving 2,3-diaryl pyrazoles in moderate to good yields.
The facile and stereoselective synthesis of pyrrolidine β-amino acids via copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition
A highly efficient copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition was developed, which provides a straightforward and efficient pathway to highly functionalized free pyrrolidine β-amino acids.
Suzuki coupling for preparation of allenes – ligand effects and chirality transfer
o-(Diphenylphosphino)benzaldehyde has been identified as the effective ligand for the coupling of propargylic carbonates and organoboronic acids under mild conditions.
Rh(I)-Catalyzed coupling of 2-bromoethyl aryldiazoacetates with tertiary propargyl alcohols through carbene migratory insertion
A Rh(I)-catalyzed cross-coupling of 2-bromoethyl aryldiazoacetates with tertiary propargyl alcohols has been successfully achieved.
[2.2]Paracyclophane-based N-heterocyclic carbene as efficient catalyst or as ligand for copper catalyst for asymmetric α-silylation of N-tosylaldimines
A carbene precursor plays a dual role as both an organocatalyst and as a ligand for the copper catalyst in asymmetric silylation.
Manganese-catalysed hydroperoxidation of carbon–carbon double bonds using molecular oxygen present in air and hydroxylamine under ambient conditions
A highly efficient manganese-catalysed hydroperoxidation of carbon–carbon double bonds of enynes as well as styrene derivatives using N-hydroxyphthalimide, N-hydroxybenzotriazole or N-hydroxysuccinimide was developed.
A new approach toward the synthesis of 2,4-bis(fluoroalkyl)-substituted quinoline derivatives using fluoroalkyl amino reagent chemistry
The present work describes the unprecedented use of Fluoroalkyl Amino Reagents (FARs) to afford 2,4-bis(fluoroalkyl)-substituted quinoline derivatives in two steps under mild reaction conditions, in good yields and with a very good regioselectivity.
Iterative catalyst controlled diastereodivergent synthesis of polypropionates
Polypropionates are synthesized using a combination of a copper-catalyzed asymmetric allylic alkylation, ruthenium-catalyzed cross-metathesis and iridium-catalyzed asymmetric allylic etherification.
Synthesis of 2,3-dihydrobenzofurans via the palladium catalyzed carboalkoxylation of 2-allylphenols
A new Pd-catalyzed alkene carboalkoxylation strategy for the preparation of 2,3-dihydrobenzofurans is described.
Switching between intermolecular and intramolecular reactions using flow microreactors: lithiation of 2-bromo-2′-silylbiphenyls
Switching between the intermolecular reaction and the intramolecular reaction was achieved at will using flow microreactors.
Considering organic mechanisms and the optimization of current flow in an electrochemical oxidative condensation reaction
Careful consideration of the chemical mechanism for an oxidative condensation reaction led to improved current flow for the electrolysis.
Catalytic asymmetric direct-type 1,4-addition reactions of simple esters
Catalytic asymmetric 1,4-addition reactions of simple esters have been developed. The desired reactions proceeded smoothly with high enantioselectivities.
Rhodium/copper-cocatalyzed annulation of benzylamines with diazo compounds: access to fused isoquinolines
Benzylamines undergo C–H activation and aerobic coupling with diazo compounds, leading to the synthesis of fused isoquinolines. This occurs via a mild synergistic rhodium- and copper-catalyzed process.
Hyperbranched supramolecular polymer constructed from twisted cucurbituril and porphyrin via host–guest interactions
A novel supramolecular polymer was constructed between Q host and 5,10,15,20-tetrakis(N-butyl-4-pyridinium)porphyrin tetrabromide guest depending on the host–guest interactions, representing the first cucurbituril-involved host–guest supramolecular polymer.
Approach to the synthesis of the C1–C11 and C14–C18 portion of Leucascandrolide A
An iterative asymmetric hydration of dienoates approach to Leucasndrolide A was explored.
Pd(II)-catalyzed direct functionalization of C–H bonds of benzamides for synthesis of 1,1-difluoro-1-alkenes
Pd-catalyzed difluoroallylation of unactivated C(sp2)–H bonds with readily available Rf-Br reagents is described.
Bismuth(III) triflate-catalysed tandem cyclisations towards complex polycyclic ethers
A series of complex polycyclic ethers have been synthesised under very mild conditions using a low catalyst loading of bismuth(III) triflate.
Reaction of alkenecarboxylic acids with isocyanates via rhodium(III)-catalyzed C–H activation: a versatile route to cyclic imides
A versatile cascade route to cyclic imides via direct functionalization of the β-alkenyl C–H bond of alkenoic acids was developed.
Stimuli-responsive supramolecular gel constructed by pillararene-based pseudorotaxanes via orthogonal metal–ligand coordination and hydrogen bonding interaction
A supramolecular polyrotaxane constructed by pillararene-based pseudorotaxanes via the incorporation of metal–ligand coordination could further self-assemble to form a stimuli-responsive supramolecular gel at high concentration.
Synthesis of trifluoromethylthiolated azacalixarenepyridines from the Cu(II)-mediated direct trifluoromethylthiolation reaction of arenes via reactive arylcopper(III) intermediates
Cu(II)-mediated arene C–H bond trifluoromethylthiolation with Me4NSCF3 proceeds via arylcopper(III) intermediates to produce functionalized azacalixarenepyridine macrocycles.
Metal-free borylation of electron-rich aryl (pseudo)halides under continuous-flow photolytic conditions
A photochemical borylation of electron-rich aryl (pseudo)halides via a triplet aryl cation mechanism has been described.
Synthesis of 2,5-disubstituted pyrroles via dehydrogenative condensation of secondary alcohols and 1,2-amino alcohols by supported platinum catalysts
2,5-Disubstituted pyrroles are synthesized by acceptorless dehydrogenative reaction of 1,2-aminoalcohols and secondary alcohols by Pt/carbon catalyst.
A general photoinduced electron transfer-directed chemoselective perfluoroalkylation of N,N-dialkylhydrazones
The first metal-free, initiator-free, and general photochemical perfluoroalkylation of a variety of N,N-dialkylhydrazones was developed at room temperature in the absence of any external photocatalyst.
Catalytic asymmetric α-amination of β-keto esters and β-keto amides with a chiral N,N′-dioxide–copper(I) complex
The highly efficient asymmetric α-amination of β-keto esters and β-keto amides was realized by using a chiral N,N′-dioxide/Cu(I) complex. Under mild reaction conditions, a series of chiral α-amino dicarbonyl compounds were obtained in good result.
Enantioselective gold-catalyzed intermolecular [2 + 2]-cycloadditions of 3-styrylindoles with N-allenyl oxazolidinone
A series of novel chiral monophosphine ligands Xiang-Phoses were designed and have been applied to the enantioselective gold-catalyzed intermolecular [2 + 2]-cycloaddition of 3-styrylindoles 1 with N-allenyl oxazolidinone 2.
Synthesis of carbamates from amines and N-tosylhydrazones under atmospheric pressure of carbon dioxide without an external base
A synthetic method to carbamates from amines and N-tosylhydrazones in the presence of 1 atm of carbon dioxide was developed.
Copper(I)-catalyzed sulfonylation of (2-alkynylaryl)boronic acids with DABSO
The scaffold of benzo[b]thiophene 1,1-dioxides can be easily constructed through a copper(I)-catalyzed insertion of sulfur dioxide into (2-alkynylaryl)boronic acids. The reaction proceeds via insertion of sulfur dioxide and subsequent intramolecular 5-endo cyclization.
Generation of N-aminosulfonamides via a photo-induced fixation of sulfur dioxide into aryl/alkyl halides
A catalyst-free aminosulfonylation through insertion of sulfur dioxide with aryl/alkyl halides enabled by photoenergy is presented. Under ultraviolet irradiation, a three-component reaction of aryl/alkyl halides, sulfur dioxide, and hydrazines proceeds under mild conditions without any metals or photo-redox catalysts.
Epoxy and aziridinyl enolsilanes in diastereoselective inter- and intramolecular Friedel–Crafts alkylations
Diastereoselective Friedel–Crafts reactions of optically pure epoxy enolsilanes afford enantiomerically-enriched β-hydroxy-α-arylketones. Aziridinyl enolsilanes react in an analogous manner.
Visible-light promoted intermolecular halofunctionalization of alkenes with N-halogen saccharins
A simple and efficient visible-light promoted intermolecular haloamination and haloetherification of alkenes was reported.
Pd(II)-catalyzed β-C–H arylation of O-methyl ketoximes with iodoarenes
A Pd(II)-catalyzed selective β-arylation of O-methyl ketoximes was developed using iodoarenes as the coupling partners.
Gold-catalyzed tandem synthesis of bioactive spiro-dipyrroloquinolines and its application in the one-step synthesis of incargranine B aglycone and seneciobipyrrolidine (I)
The Au-catalyzed tandem reaction provided simple and efficient access to spiro-dipyrroloquinolines and incargranine B aglycone and (±)-seneciobipyrrolidine (I).
Pd/norbornene-catalyzed sequential ortho-C–H alkylation and ipso-alkynylation: a 1,1-dimethyl-2-alkynol strategy
A palladium/norbornene-catalyzed ortho-C–H alkylation and ipso-alkynylation reaction for the synthesis of 2-alkyl-1-alkynyl arenes was reported, where the use of bulky 1,1-dimethyl-2-alkynols led to significant suppression of the formation of O-alkylation and norbornene alkynylation by-products.
Access to bicyclic hydroxamate macrocycles via intramolecular aza-(4 + 3) cyloaddition reactions of aza-oxyallylic cation intermediates
The intramolecular aza-(4 + 3) cycloaddition reactions of in situ generated aza-oxyallylic cations and furans have been reported for the construction of medium sized hydroxamate macrocycles.
Exploiting ortho-substitution effect on formation of oxygen-containing paracyclophane through ring-closing metathesis
The synthesis of strained paracyclophanes is facilitated by ortho-substitution effect on phenyl ring.
About this collection
Read some of the best research published by Organic Chemistry Frontiers in 2016. These articles are recommended by OCF referees as being of significant novelty and interest.