Photoinduced Copper-Catalyzed Coupling of Acylsilanes with Indoles or Electron-Rich Arenes.

Although the reactions of electrophilic Fischer-type metal siloxycarbenes catalytically generated in situ from acylsilanes with a single nucleophile have been documented, the coupling of acylsilanes with two nucleophiles remains unexplored. Herein, we demonstrate that acylsilanes can act as effective cationic carbyne equivalents under visible-light-driven copper catalysis, enabling their coupling with diverse indoles or electron-rich arenes. This strategy operates under mild, redox-neutral conditions and exhibits broad functional group compatibility.

Photocatalytic Radical Cascade Cyclization of -(-Cyanobiaryl)acrylamides with Sulfonyl Chlorides.

A photoredox-catalyzed radical cascade cyclization of -(-cyanobiaryl)acrylamides with sulfonyl chlorides for the construction of sulfonyl-containing pyrido[4,3,2-]phenanthridines has been disclosed. The developed synthetic tool tolerates a broad range of sulfonyl chlorides to undergo a cascade sequence, including sulfonyl radical addition, nitrile insertion, and cyclization.

Radical relay strategy for the construction of alkylsulfonated indolo[2,1-]isoquinoline-6(5)-ones SO insertion/Smiles rearrangement.

A new radical relay approach for the efficient construction of alkylsulfonated indolo[2,1-]isoquinoline-6(5)-ones in moderate to good yields under mild conditions SO insertion/Smiles rearrangement/intramolecular cyclization is developed. This approach utilizes 4-alkyl substituted Hantzsch esters as alkyl radical sources and further undergoes SO insertion to obtain alkylsulfonyl radical species, which avoids the use of unstable alkyl sulfonyl chlorides and highly toxic sulfonyl hydrazides. Additionally, this method for the direct assembly of alkylsulfonated polycyclic molecule skeletons displays high chemical selectivity, broad substrate scope, and step-economy.

Radical Cascade Cyclization of -(-Cyanobiaryl)acrylamides with Sulfonium Salts via Synergetic Photoredox and Copper Catalysis.

As the magic methyl effect is well acknowledged in pharmaceutical molecules, the development of simple and efficient methods for the installment of methyl groups on complex molecules is highly coveted. Hence, we provide a general strategy for radical cascade cyclization of -(-cyanobiaryl)acrylamides by utilizing sulfonium salts as the sources of methyl radical and merging photoredox and copper catalysis. This novel protocol can access a wide variety of methylation or remote thioether-substituted benzo-fused -heterocycle derivatives, which can be easily transformed into diverse highly valuable sulfone and sulfoximine compounds via late-stage diversification.

Photocatalytic radical cyclization of -(-cyanobiaryl)acrylamides with oxime esters.

A visible-light-mediated radical cascade cyclization of -(-cyanobiaryl)acrylamides with oxime esters for the assembly of acyl-containing pyrido[4,3,2-]phenanthridines has been developed. The present protocol tolerates a wide range of oxime esters through a single reaction fragmentation, radical addition, nitrile insertion, and cyclization under mild conditions.

Oxidative Difunctionalization of -Aryl Bicyclobutyl Amides with Aldehydes: Divergent Synthesis of Acylated and Alkylated 3-Spirocyclobutyl Oxindoles.

An efficient and operationally simple oxidative radical difunctionalization of -aryl bicyclobutyl (BCB) amides with aldehydes is described. It was found that acylated 3-spirocyclobutyl oxindoles were generated from the coupling of BCB-amides and aromatic aldehydes, while reactions gave exclusively decarbonylative alkylarylation products using alkyl aldehydes as radical precursors.

Photoredox Ring Opening 1,2-Alkylarylation of Alkenes with Sulfonium Salts Toward Thioether-Substituted Oxindoles.

A novel strategy for the difunctionalization of electron-deficient alkenes with aryl sulfonium salts to access remote sulfur-containing oxindole derivatives by using in situ-formed copper(I)-based complexes as a photoredox catalyst is presented. This method enables the generation of the C(sp)-centered radicals through site selective cleavage of the C-S bond of aryl sulfonium salts under mild conditions. Moreover, the oxidation reactions of desired products provide a new strategy for the preparation of sulfoxide or sulfone-containing compounds.

Electro-oxidative three-component cascade coupling of isocyanides with elemental sulfur and amines for the synthesis of 2-aminobenzothiazoles.

2-Aminobenzothiazoles are commonly encountered in various functional compounds. Herein, we disclose an electro-oxidative three-component reaction for the effective synthesis of 2-aminobenzothiazoles under mild conditions, utilizing non-toxic and abundant elemental sulfur as the sulfur source. Both aliphatic amines and aryl amines demonstrate good compatibility at room temperature, highlighting the broad functional group tolerance of this approach.

Photoredox-Catalyzed Alkylarylation of -Aryl Bicyclobutyl Amides with α-Carbonyl Alkyl Bromides: Access to 3-Spirocyclobutyl Oxindoles.

A visible-light-induced radical alkylarylation of -aryl bicyclobutyl amides with α-carbonyl alkyl bromides for the synthesis of functionalized 3-spirocyclobutyl oxindoles is described in which β-selective radical addition of the alkyl radical to -aryl bicyclobutyl amides forms a key radical intermediate followed by interception with intrinsic arene functional group. This approach can be applicable to a wide range of α-carbonyl alkyl bromides, including primary, secondary, and tertiary α-bromoalkyl esters, ketones, nitriles, and nitro compounds.

Recent advances in ring-opening of cyclobutanone oximes for capturing SO, CO or O a radical process.

Cyclobutanone oximes and their derivatives are pivotal core structural motifs in organic chemistry. Iminyl-radical-triggered C-C bond cleavage of cyclobutanone oximes delivers an efficient strategy to produce stable distal cyano-substituted alkyl radicals, which can capture SO, CO or O to form cyanoalkylsulfonyl radicals, cyanoalkylcarbonyl radicals or cyanoalkoxyl radicals under mild conditions. In the past several years, cyanoalkylsulfonylation/cyanoalkylcarbonyaltion/cyanoalkoxylation has attracted a lot of interest.

Cu-catalyzed oxidative denitrogenation of 3-aminoindazoles for the synthesis of isoquinolinones.

A Cu-catalyzed oxidative dual arylation of active alkenes the cleavage of two C-N bonds of 3-aminoindazoles is presented for constructing isoquinolinones. Importantly, 3-aminoindazoles are used as efficient arylating agents through a radical process. This method has a good substrate scope and functional group compatibility.

Iron-Promoted Oxidative Alkylation/Cyclization of Ynones with 4-Alkyl-1,4-dihydropyridines: Access to 2-Alkylated Indenones.

An iron-promoted oxidative tandem alkylation/cyclization of ynones with 4-alkyl-substituted 1,4-dihydropyridines for the efficient synthesis of 2-alkylated indenones is described. The process occurs oxidative homolysis of a C-C σ-bond in 1,4-dihydropyridines to generate an alkyl radical followed by the addition of C-C triple bonds in ynones and intramolecular cyclization. A wide range of alkyl radicals could be efficiently transferred to generate a series of synthetically useful 2-alkylated indenones with excellent selectivity under mild conditions.

Alkylation/Ipso-cyclization of Active Alkynes Leading to 3-Alkylated Aza- and Oxa-spiro[4,5]-trienones.

A method for the preparation of 3-alkylated spiro[4.5]trienones alkylation/ipso-cyclization of activated alkynes with 4-alkyl-DHPs under transition-metal-free conditions is proposed. This alkylation successively undergoes the generation of alkyl radicals, addition of alkyl radicals to the alkynes, and intramolecular ipso-cyclization.

Transition-metal-free alkylation strategy: facile access to alkylated oxindoles alkyl transfer.

The transition-metal-free alkylation/cyclization of activated alkenes using Hantzsch ester derivatives as effective alkyl reagents is described. A wide variety of valuable oxindoles was constructed in a single step with excellent selectivity. The reaction occurs through the formation of alkyl radical species followed by the tandem addition/annulation of olefins under oxidative conditions.

Recent advances in total syntheses of natural products containing the benzocycloheptane motif.

Covering: 2010 to 2020Benzocycloheptane is a fundamental and unique structural motif found in pharmaceuticals and natural products. The total syntheses of natural products bearing the benzocycloheptane subunit are challenging and there are only a few efficient approaches to access benzocycloheptane. Thus, new methods and innovative strategies for preparing such natural products need to be developed.

Synthetic applications of type II intramolecular cycloadditions.

Type II intramolecular cycloadditions ([4+2], [4+3], [4+4] and [5+2]) have emerged recently as an efficient and powerful strategy for the construction of bridged ring systems. In general, type II cycloadditions provide access to a wide range of bridged bicyclo[m.n.

Synthetic Study toward the Total Synthesis of Taxezopidines A and B.

A concise synthetic approach to construct the [6,8,6]-tricyclic core of taxezopidines A and B, which contains a synthetically challenging bridged bicyclo[5.3.1]undecane ring system bearing most of the desired functionalized groups and stereocenters, has been established.

Asymmetric Total Synthesis of Cyclocitrinol.

The first and asymmetric total synthesis of cyclocitrinol, an unusual C25 steroid, has been accomplished in a linear sequence of 18 steps from commercially available compound 11. The synthetically challenging bicyclo[4.4.

A phase II study of concurrent chemoradiotherapy combined with a weekly paclitaxel and 5-fluorouracil regimen to treat patients with advanced oesophageal carcinoma.

Background: A phase II study was performed to investigate the safety and efficacy of weekly doses of combined paclitaxel and 5-fluorouracil (5-FU) with concurrent radiation therapy, followed by 2 cycles of consolidation chemotherapy to treat patients with advanced oesophageal carcinoma.

Methods: The eligibility criteria included local, advanced, newly diagnosed and postoperative local regional lymph node metastasis; an Eastern Cooperative Oncology Group (ECOG) score of ≤ 2; and adequate organ function. Patients received chemoradiotherapy consisting of radiotherapy (50.

Long-term results of paclitaxel plus cisplatin with concurrent radiotherapy for loco-regional esophageal squamous cell carcinoma.

Aim: To evaluate the long-term effectiveness and late toxicities of paclitaxel (PTX) plus cisplatin (DDP) with concurrent radiotherapy for locally advanced esophageal squamous cancer.

Methods: Between 2008 and 2011, 76 patients were enrolled in a phase II study on the treatment of loco-regionally advanced esophageal cancer with radiotherapy (68.4 Gy/44 fractions or 61.

Metal-Free Radical [2+2+1] Carbocyclization of Benzene-Linked 1,n-Enynes: Dual C(sp(3))-H Functionalization Adjacent to a Heteroatom.

A new metal-free oxidative radical [2+2+1] carbocyclization of benzene-linked 1,n-enynes with two C(sp(3))-H bonds adjacent to the same heteroatom is described. This method achieves two C(sp(3))-H oxidative functionalizations and an annulation, thus providing efficient and general access to a variety of fused five-membered carbocyclic hydrocarbons.

Palladium-catalyzed oxidative Heck-type alkylation/aryl migration/desulfonylation between alkenes with α-carbonyl alkyl bromides.

A new Pd(II)-catalyzed alkene oxidative difunctionalization initiated by Heck insertion has been developed for the selective synthesis of acyclic and cyclic all-carbon quaternary stereocenters, which achieves an oxidative Heck-type alkylation, aryl migration, and desulfonylation sequence and represents a different input from those previously used Heck coupling in synthesis is reported.

Copper-catalyzed oxidative coupling of acids with alkanes involving dehydrogenation: facile access to allylic esters and alkylalkenes.

We here describe a new copper-catalyzed oxidative coupling of acids with alkanes for the selective synthesis of allylic esters and alkylalkenes. This method achieves multiple dehydrogenation and esterification, representing a new unactivated C(sp(3))-H oxidative esterification of acids with common alkanes.

Palladium-catalyzed oxidative difunctionalization of alkenes with α-carbonyl alkyl bromides initiated through a Heck-type insertion: a route to indolin-2-ones.

The oxidative interception of various σ-alkyl palladium(II) intermediates with additional reagents for the difunctionalization of alkenes is an important research area. A new palladium-catalyzed oxidative difunctionalization reaction of alkenes with α-carbonyl alkyl bromides is described, in which the σ-alkyl palladium(II) intermediate is generated through a Heck insertion and trapped using an aryl C(sp(2))-H bond. This method can be applied to various α-carbonyl alkyl bromides, including primary, secondary, and tertiary α-bromoalkyl esters, ketones, and amides.