Themed collection HOT articles in Organic Chemistry Frontiers in 2015
Regioselective palladium(II)-catalyzed aerobic oxidative Heck-type C3 alkenylation of sulfocoumarins
An efficient method for the direct C–H olefination of sulfocoumarins with a wide range of alkenes is developed. Moreover, O2 was successfully utilized as the sole oxidant for the oxidative Heck reaction. This approach enables the rapid generation of various 3-alkenylated sulfocoumarins.
Rhodium catalysed conversion of carbenes into ketenes and ketene imines using PNN pincer complexes
PNN pincer-type rhodium complexes catalyze ketene and ketene imine synthesis, using CO or an isocyanide and a carbene precursor.
Direct borylation of benzyl alcohol and its analogues in the absence of bases
Direct borylation of arylmethanols to synthesize important and useful benzylboronates was carried out through Pd(OAc)2-catalyzed sp3 C–O activation.
Stereoselective formation of chiral trans-4-hydroxy-5-substituted 2-pyrrolidinones: syntheses of streptopyrrolidine and 3-epi-epohelmin A
A highly diastereoselective approach for synthesis of trans-4-hydroxy-5-substituted 2-pyrrolidinones has been developed. The streptopyrrolidine and 3-epi-epohelmin A were synthesized by this one-pot cascade protocol.
Silver-catalyzed [3 + 2] cycloaddition of isocyanides with diazo compounds: new regioselective access to 1,4-disubstituted-1,2,3-triazoles
An unprecedented silver-catalyzed 1,3-dipolar cycloaddition reaction of isocyanides with diazo compounds to afford 1,4-disubstituted 1,2,3-triazoles is realized.
Speciation and kinetic study of iron promoted sugar conversion to 5-hydroxymethylfurfural (HMF) and levulinic acid (LA)
Identification of catalytic species and their contributions in iron catalyzed sugar conversion to hydroxymethylfurfural and levulinic acid.
Palladium-catalyzed methylene C(sp3)–H arylation of the adamantyl scaffold
A palladium-catalyzed C(sp3)–H arylation of adamantane at the methylene position with the assistance of an amide group was developed.
Cu-Mediated 2,2,2-trifluoroethylation of terminal alkynes using 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123)
Cu-Promoted coupling reactions of HCFC-123 with terminal alkynes give trifluoroethylated internal alkynes.
Efficient synthesis of P-chiral biaryl phosphonates by stereoselective intramolecular cyclization
A series of P-chiral biaryl phosphonates were efficiently synthesized from diaryl 2-bromo arylphosphonates in high yields (up to 92%) and good enantioselectivities (up to 88% ee) through a palladium-catalyzed desymmetric intramolecular cyclization with a P-chiral biaryl monophosphorus ligand.
Organoselenium-catalyzed synthesis of indoles through intramolecular C–H amination
An efficient approach for organoselenium-catalyzed synthesis of indoles via intramolecular C–H amination has been developed.
A thermally stable pH-responsive “supramolecular buckle” based on the encapsulation of 4-(4-aminophenyl)-N-methylpyridinium by cucurbituril
A CB-based host-guest system forms a thermally stable 1 : 2 complex under neutral conditions and transforms into a 1 : 1 complex upon acidification, which makes it a “supramolecular buckle” to fabricate pH-responsive materials at elevated temperatures.
Intramolecular C–H insertion vs. Friedel–Crafts coupling induced by silyl cation-promoted C–F activation
Silyl cation-promoted aryl C–F activation can lead to formal C–H activation and the formation of new C(ar)–C(alkyl) bonds.
Copper-mediated oxidative difluoromethylation of terminal alkynes with TMSCF2H
A copper-mediated oxidative coupling of terminal alkynes and TMSCF2H has been described for the preparation of various difluoromethylated alkynes.
A novel dynamic pseudorotaxane based on a mono-biotin-functionalized pillararene
A stable pillararene-based pseudorotaxane P1′ was synthesized by the click reaction, which exhibited a dynamic slow disassembly process upon adding a strong-polar solvent or competitive guest. Moreover, this dynamic behavior might be used as a switch to turn on or off the bioactivity of the biotin moiety in aqueous solution.
Syntheses of sceptrins and nakamuric acid and insights into the biosyntheses of pyrrole–imidazole dimers
The SET-promoted homodimerization of pyrrole–imidazole alkaloids is a stepwise reaction favoring the [2 + 2] pathway.
Sulfone promoted Rh(III)-catalyzed C–H activation and base assisted 1,5-H shift strategy for the construction of seven-membered rings
A sequence of Rh(III)-catalyzed C–H cleavage, 1,5-H shift and intramolecular allene insertion was developed for the construction of seven-membered rings.
Catalytic enantioselective synthesis of quaternary 3,3′-indolyloxindoles by combination of Rh(II) complexes and chiral phosphines
Rh(II)/chiral phosphine combined catalysis has been developed for a highly efficient sequential C–H functionalization/asymmetric allylation or Michael addition reaction to afford a diverse range of quaternary 3,3′-indolyloxindole derivatives.
Palladium-catalyzed direct ortho C–O bond construction of azoxybenzenes with carboxylic acids and alcohols
A Pd(II) catalyzed C–O bond formation of azoxybenzenes has been developed.
Formal synthesis of (−)-platensimycin
An efficient formal synthesis of (−)-platensimycin was completed by using a tandem C–H oxidation/C–C coupling (cyclization)/rearrangement as the key step.
Palladium-catalyzed intramolecular rearrangement of vinylidenecyclopropanes through C–C bond activation
An intramolecular rearrangement of vinylidenecyclopropanes to dimethylenecyclopropanes through C–C bond activation has been developed.
Mechanistic studies on C–C reductive coupling of five-coordinate Rh(III) complexes
C–C reductive coupling of rare five-coordinate rhodium(III) complexes has been studied in detail.
Pd-catalyzed Heck cyclization and in situ hydrocarboxylation or hydromethenylation via a hydrogen borrowing strategy
A palladium-catalyzed Heck cyclization and in situ hydrocarboxylation reaction was developed using chloroform as a one-carbon elongation reagent.
Ruthenium-catalyzed alkoxycarbonylation of alkenes using carbon monoxide
The first ruthenium-catalyzed alkoxycarbonylation of alkenes with alcohols using carbon monoxide as carbonyl source is realized.
A challenging Heck reaction of maleimides
A difficult Heck reaction of base-sensitive maleimides is realized by using a weak base in a carbonate solvent.
Sulfur-containing stable five-membered “cycloallene” complexes: 1-thia-2-zircona- and 1-thia-2-titanacyclopenta-3,4-dienes
Stable five-membered sulfur-containing metallacyclic allenes, 1-thia-2-metallacyclopenta-3,4-diene, were synthesized from the reactions of low-valent zirconocene or titanocene with alkynylthioamides.
Highly efficient and practical hydrogenation of olefins catalyzed by in situ generated iron complex catalysts
In situ generated Fe catalysts from bench-stable Fe(II) complexes and LiAlH4 exhibited unprecedented activity for the hydrogenation of olefins.
A one-pot dilithiation–lithium–zinc exchange–Negishi coupling approach to 2,6-di(hetero)aryl substituted dithienothiazines – a novel class of electronically fine-tunable redox systems
2,6-Di(hetero)aryl substituted dithienothiazines with fine-tunable electronic properties are efficiently accessible by lithiation–lithium–zinc exchange–Negishi cross-coupling in a one-pot fashion.
Regio- and stereoselective synthesis of α-hydroxy-β-azido tetrazoles
Unreported α-hydroxy-β-azido tetrazoles are prepared in a single step and mild conditions from readily available epoxy nitriles.
New building blocks for iminosugars: a concise synthesis of polyhydroxylated N-alkoxypiperidines through an intramolecular azepine ring contraction
Polyhydroxylated piperidines are a functionally rich class of biologically active molecules that have broad therapeutic potential.
Meinwald-type rearrangement of monosubstituted epoxides to methyl ketones using an [Al porphyrin]+[Co(CO)4]− catalyst
A Meinwald-type rearrangement of monosubstituted epoxides to methyl ketones using a well-defined aluminum porphyrin catalyst is reported.
Pd(II)-catalyzed asymmetric addition of arylboronic acids to cyclic N-sulfonyl ketimine esters and a DFT study of its mechanism
A highly efficient palladium-catalyzed asymmetric arylation of cyclic ketimine esters is developed, which provides the desired product in up to 99% yield with up to 99% ee. The mechanism of enantioselection is studied using DFT calculation.
TEMP and copper cocatalyzed oxygenation of ketones with molecular oxygen: chemoselective synthesis of α-ketoesters
A practical approach to α-ketoesters through TEMP and copper cocatalyzed chemoselective oxidative coupling of methyl ketones with alcohols is developed.
Alkyl- and aryl-thioalkylation of olefins with organotrifluoroborates by photoredox catalysis
A new photocatalytic alkyl- and aryl-thioalkylation of electron-deficient olefins using organotrifluoroborates has been developed.
Au(I) π-bis(tert-butyldimethylsilyl)acetylene triphenylphosphine complex, an effective pre-catalyst for Au(I)-catalyzed reactions
A [Ph3PAu]+ η2-alkyne π complex is found to be shelf-stable and effective for a range of the Au(I)-catalyzed alkyne π activation reactions.
Phase-transfer-catalyzed asymmetric desymmetrizations of cyclopentanones
Highly enantioselective phase-transfer-catalyzed epoxide-opening reaction and isomerization of cyclopentanones were achieved.
Selective syntheses of leuconolam, leuconoxine, and mersicarpine alkaloids from a common intermediate through regiocontrolled cyclizations by Staudinger reactions
Selective syntheses of alkaloids bearing distinct core structures were enabled by chemically programmed polycyclizations using water as a switch.
Indolizine synthesis via Cu-catalyzed cyclization of 2-(2-enynyl)pyridines with nucleophiles
Cu-catalyzed cyclization of 2-(2-enynyl)pyridines with various nucleophiles was developed, providing efficient access to indolizine derivatives.
Gold(I)-catalyzed asymmetric [3 + 2]-cycloadditions of γ-1-ethoxyethoxy-propiolates and aldehydes
A gold-catalyzed asymmetric intermolecular [3 + 2]-cycloaddition of γ-1-ethoxyethoxy-propiolate and aldehydes by using the chiral ligand 5a or 5b is developed, which provides facile access to highly substituted 2,5-dihydrofurans in up to 84% yield with up to 97% ee.
N-heterocyclic carbene-based ruthenium-catalyzed direct amidation of aldehydes with amines
Ru-catalyzed dehydrogenative amide synthesis from aldehydes and amines was achieved, based on the idea of using a hemiaminal intermediate to generate the active Ru-hydride species.
Simple, versatile, and chemoselective reduction of secondary amides and lactams to amines with the Tf2O–NaBH4 or Cp2ZrHCl–NaBH4 system
A convenient method for the direct reduction of secondary amides and lactams to amines is reported.
Cationic Pd(II)-catalyzed cyclization of N-tosyl-aniline tethered alkynyl ketones initiated by hydropalladation of alkynes: a facile way to 1,2-dihydro or 1,2,3,4-tetrahydroquinoline derivatives
A cationic Pd(II)-catalyzed intramolecular alkyne-carbonyl reductive coupling reaction of N-tosyl-aniline tethered alkynyl ketones under transfer hydrogenation conditions to give hydroquinolines is developed.
Cu- or Fe-catalyzed C–H/C–C bond nitrogenation reactions for the direct synthesis of N-containing compounds
This tutorial account summarizes the recent progress in Cu- or Fe-catalyzed C–H/C–C bond nitrogenation reactions for the direct synthesis of N-containing compounds.
Catalytic dehydrogenative aromatization: an alternative route to functionalized arenes
Catalytic dehydrogenative aromatization has emerged as an efficient and environmentally friendly way to access functionalized arenes in recent years.
Difluoromethyl 2-pyridyl sulfone: a versatile carbonyl gem-difluoroolefination reagent
The gem-difluoroolefination of carbonyl compounds with difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) has been summarized in this tutorial account.
About this collection
Read some of the best research published by Organic Chemistry Frontiers in 2015. These articles are recommended by OCF referees as being of significant novelty and interest.