We have quantum chemically explored the competition between the SN2 and SN2′ pathways for X– + H2C═CHCH2Y (X, Y = F, Cl, Br, I) using a combined relativistic density functional theory and coupled-cluster theory approach. Bimolecular nucleophilic substitution reactions at allylic systems, i.e., Cγ═Cβ–Cα–Y, bearing a leaving-group at the α-position, proceed either via a direct attack at the α-carbon

A versatile synthesis of α-amino bisphosphonates has been achieved through one-pot interrupted Ritter-type reaction under mild conditions. The reactive Ritter intermediate nitrilium is in situ generated by treatment of nitrile with readily accessible Tf2O/HC(OR1)3, which is trapped by phosphite ester to deliver the desired product. This protocol is efficient, scalable, and well compatible with a broad

The stereoselective introduction of glycosidic bonds is of paramount importance to oligosaccharide synthesis. Among the various chemical strategies to steer stereoselectivity, participation by either neighboring or distal acyl groups is used particularly often. Recently, the use of the 2,2-dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) protection group was shown to offer enhanced stereoselective steering

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In recent years, researches on the total syntheses of Stemona alkaloids with different 5/7 bicyclic systems have attracted increasing attention, and the development momentum in this field has gradually changed from single molecule synthesis to unified syntheses of multiple molecules. Among them, the emergence of mutual transformations among Stemona alkaloids with different ring systems has indeed improved

4-Aryl-3-thiocyanatobutan-2-ones were prepared by Meerwein reactions from methyl vinyl ketone and aryldiazonium salts under copper(II) catalysis in 35–75% yields. α-Thiocyanato ketones regioselectively react with 1-methyl-3-aminopyrazole forming N-(3-pyrazolyl)-substituted 2-aminothiazoles in 80–91% yields. An ester group in position 3 of the pyrazole induced a regioselective ring-closure reaction

The affiliation of the corresponding author Xiaojie Lu was incorrect. Previously published affiliation: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhang Jiang Hi-Tech Park, Pudong, Shang-hai, 201203, China Corrected affiliation: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy

Disclosed herein is a photosensitizer-free strategy for the direct C-H difluoroalkylation of quinoxalinones and hydrazones with bromodifluoroacylarenes via visible-light-promoted Csp3-Br bond homolytic pathway. This new reaction provides the access to difluoroalkylated quinoxaline and hydrazone derivatives with excellent substrate generality under simple, mild, green, and metal-free conditions. This

The reactions of N,N -substituted enaminones with TEMPO leading to the synthesis of 2,2-dimethyl pyrrolidine functionalized new enaminones have been established by Ni(II) catalysis. Interesting ring contraction on TEMPO as well as the enaminone C-N bond amination bring new tool for generating molecular diversity of enaminones in the amino group fragment.

We have quantum chemically studied the palladium-mediated activation of C(spn)–X bonds (n = 1–3; X = F, Cl, Br, I) in the archetypal model substrates H3C–CH2–X, H2C=CH–X, and HC≡C–X by a model bare palladium catalyst, using relativistic density functional theory at ZORA-BLYP/TZ2P. The bond activation reaction barrier decreases, for all sp-hybridized carbon centers, when the substituent X of the substrate

Metallaphotoredox catalysis represents the combination of two activation modes, viz; metal-catalyzed C-H functionalization and visible-light-induced photocatalysis. This appealing dual catalysis technique has evolved as a versatile platform that has paved the way for diverse low-energy pathways for a plethora of synthetic transformations. The synergistic combination of two “green” approaches has garnered

1-Methylthio-2-arylethynes were prepared in typically good to excellent yields from aryl iodides and 1-methylthio-2-(trimethylsilyl)-ethyne by a desilylative Sonogashira process employing Pd(PPh 3 ) 2 Cl 2 (1 mol%), CuI (10 mol%), and K 2 CO 3 (6 eq) in MeOH-Et 3 N-THF (1:2:2) at rt for 16 h (16 examples, 31-96% yield). Thienyl and pyridyl iodides (all regioisomers) were similarly converted to 1-m

Sulfonyl fluorides have found diverse applications in multiple disciplines due to their reactivity and stability. Thus, exploiting the new reactivity of sulfonyl fluorides is of high importance to Sulfur (VI) Fluoride Exchange (SuFEx) chemistry. Reported herein is a three-component reaction of β-keto sulfonyl fluorides, arynes and DMF for the streamline synthesis of sulfocoumarins. The reaction proceeds

Thiiranes, the corresponding sulfur analogues of epoxides, are less studied and less encountered in literature. This might be due to the limited existing synthetic approaches for their synthesis. Herein, a mild, sustainable and efficient organocatalytic synthesis of thiiranes has been developed. Starting from olefins and utilizing the epoxidation protocol developed in the Kokotos’ group, which employs

The Cu(I)-catalyzed reaction between five-, six-, seven-, and eight-membered cyclic 1-bromoallyl tosylates and five- and six-membered cyclic 1,3-dicarbonyls in DMF at 80 °C using Cs2CO3 as a base and 2-picolinic acid as an additive selectively delivers a wide array of bisannulated 4H-pyrans in a single step with yields up to 92%. The transformations are considered to proceed as intermolecular C-al

C(aryl)–OMe bond functionalization catalyzed by cobalt(II) chloride in combination with a nacnac-type ligand and magnesium as a reductant is reported. Borylation and benzoylation of aryl methoxides are demonstrated, and C(aryl)–SMe bond borylation can be achieved under similar conditions. This is the first example of achieving these transformations using cobalt catalysis. Mechanistic studies suggest

An efficient and novel approach to accessing 3-selenylquinolines from diaryl diselenides and acyclic, selenium-free substrates is described. Preliminary mechanistic studies indicate that the combination of CuCl2 and air affords an appropriate environment for producing arylselenyl radicals that initiate the cascade cyclization of N-(2-alkynyl)anilines, forming key Se–C and C–C bonds in a single step

A nickel-catalyzed tandem Ueno–Stork cyclization is developed to enable stereoselective 1,2-dicarbofunctionalization of cyclic alkenes and efficiently build various bicyclic products. This new protocol does not involve any toxic or difficult-to-remove tin reagent and is scalable and amenable to build all-carbon quaternary centers.

Brønsted acid- and/or Lewis acid-catalyzed selective C3-allylation and formal [3 + 2]-annulation of spiro-aziridine oxindoles with allylsilanes have been demonstrated to deliver direct access to 3-allyl-3-aminomethyl oxindoles and 5-silyl methyl spiro[pyrrolidine-3,3′-oxindoles], respectively. The acid-catalyzed methods do not provide any stereoselectivity when chiral spiroaziridines are used. However

A novel strategy for the synthesis of 1-pyrrolines based on formal [4 + 1] annulation of 2-alkyl-2H-azirines with diazocarbonyl compounds has been developed. This one-pot approach includes the Rh(II)-catalyzed formation of 4-alkyl-2-azabuta-1,3-dienes, followed by the DBU-promoted cyclization, and features a good substrate tolerance. The 1-pyrrolines containing an ester group at the C3 were prepared

Chiral bicyclic N,O-acetal isoserine derivatives have been synthesized by an acid-catalyzed tandem N,O-acetalization/intramolecular transcarbamoylation reaction between conveniently protected l-isoserine and 2,2,3,3-tetramethoxybutane. The delicate balance of the steric interactions between the different functional groups on each possible diastereoisomer controls their thermodynamic stability and hence

We report the synthesis of iminosugar C,C-glycosides starting from 6-azidoketopyranoses. Their Staudinger-azaWittig-mediated cyclization provided bicyclic N,O-acetals, which were stereoselectively opened with AllMgBr to afford β-hydroxyazepanes with a quaternary carbon α to the nitrogen. Their ring contraction via a β-aminoalcohol rearrangement produced the six-membered l-iminosugars with two functional

Palladium-catalyzed regioselective [5 + 1] annulation reactions of vinyl aziridines/epoxides with ClCF2COONa have been developed. Significantly, vinyl aziridines/epoxides act as heteroatom-containing five-atom synthons, and commercially available and cheap ClCF2COONa acts as the source of carbonyl serving as a difluorocarbene precursor. This protocol provides an efficient and practical method for the

Aza-helicenes are one of the most important series of heterohelicenes; herein, a series of novel aza-helicenes (5H, 6H, 6S, and 8S) were prepared via Bischler–Napieralski cyclization, and the interconversion dynamic process of these aza-helicenes was revealed using density functional theory calculations. The novel nitrogen-doped [6]helicene (6H) possesses a very high interconversion energy barrier

A novel one-pot reaction of anilines with acetylenedicarboxylate diesters in the presence of boron trifluoride, iodine, and trifluoroacetic acid or methylsulfonic acid has been developed under solvent-free ball-milling conditions, affording a variety of polysubstituted 1,2-dihydroquinolines bearing multiple ester groups in moderate to excellent yields. The present protocol features mild reaction conditions

Here, we report a novel and facile protocol for the synthesis of benz[c,d]indol-2-imines via palladium-catalyzed C–C and C–N coupling of 8-halo-1-naphthylamines with isocyanides in a single step. The reaction features broad substrate scopes and mild conditions, providing an efficient alternative for the construction of antiproliferative agents and BET bromodomain inhibitors. If 0.1 mL of H2O was added

An efficient and convenient method to synthesize 6-oxyalkylated 1,2,4-triazine-3,5(2H, 4H)-diones has been developed via visible-light-induced cross-dehydrogenative coupling reaction between 1,2,4-triazine-3,5(2H, 4H)-diones and ethers with a wide range of functional group tolerance. The present transformation employs the cheap and low-toxic 2-tert-butylanthraquinone as a metal-free photocatalyst and

An Fe(OTf)2-catalyzed three-component coupling reaction of α,β,γ,δ-unsaturated carbonyl compounds with alkylsilyl peroxides in the presence of certain heteronucleophiles (ROH and indole) is realized under mild reaction conditions. A variety of α,β,γ,δ-diene carbonyl substrates with different substituents were successfully employable via combination with several different alkylsilyl peroxides. This

Boron/nitrogen-doped fluoranthenes, a new class of BN-doped cyclopenta-fused polycyclic aromatic hydrocarbons, were synthesized via pyrrolic-type nitrogen directed C–H borylation. Regioselective bromination of BN-fluoranthene (3a) gave mono- and dibrominated BN-fluoranthenes. The halogenated BN-fluoranthene (3b) can undergo various of further cross-coupling reactions to deliver a series of BN-fluoranthenes

Differentiation of heterocyclic isomers by solution 1H, 13C, and 15N NMR spectroscopy is often challenging due to similarities in their spectroscopic signatures. Here, 13C{14N} solid-state NMR spectroscopy experiments are shown to operate as an “attached nitrogen test”, where heterocyclic isomers are easy to distinguish based on one-dimensional nitrogen-filtered 13C solid-state NMR. We anticipate that

A new class of tailor-made push–pull isoindole fluorophores has been synthesized through the combination of Suzuki coupling and Knoevenagel reactions. The efficient synthetic strategy rendered the isoindole scaffold as the π-bridge and the isolation spacer and provided dyes bearing various types of electron donors and electron acceptors for manipulating their energy gaps and tuning their absorptions