Cu-Catalyzed Carbocyclization for General Synthesis of N-Containing Heterocyclics Enabled by BrCF2COOEt as a C1 Source.

A practical and efficient copper-catalyzed carbocyclization of 2-functionalized anilines with ethyl bromodifluoroacetate has been developed. Ethyl bromodifluoroacetate is employed as the C1 source via quadruple cleavage in this transformation. This reaction can afford a variety of N-containing heterocyclics with satisfactory yields and excellent functional group compatibility.

Tandem Sulfonylative Annulation/Halogenation of 1,7-Enynes with Sodium Sulfinate and TBAX for the Assembly of 4-Methylenechromanes.

An effective and stereoselective synthesis of halogenated (E)-4-methylenechromanes with a sulfonyl group was developed via the copper-catalyzed sulfonylative annulation/halogenation of 1,7-enynes, in which sodium sulfinates were used as the sulfonyl reagents and tetrabutylammonium halide provided the halogen sources. The formed alkenyl C-X bonds were valuable and can efficiently undergo the subsequent hydrolysis, alkenylation, alkynylation, arylation, alkylthiolation, and alkoxylation to furnish a series of highly functionalized 4-methylenechromanes.

Synthesis of Trifluoromethylated Dibenzoxepines via Palladium-Catalyzed Tandem C-O Bond Formation/C-H Arylation.

A palladium-catalyzed cyclization reaction of phenols with trifluoromethyl-containing ortho-bromo-ß-chlorostyrenes has been developed. In the presence of palladium(II) acetate, tricyclohexylphosphine, and cesium carbonate, a variety of 6-trifluoromethyldibenzo[b,d]oxepines were prepared in moderate to good yields through the tandem O-alkenylation of general phenols and subsequent C-H arylation.

TBAI-Mediated Cyclization and Methylsulfonylation of Propargylic Amides with Dimethyl Sulfite.

A tetramethylammonium iodide (TBAI)-mediated cyclization and methylsulfonylation of propargylic amides enabled by dimethyl sulfite as a SO2 surrogate and methyl source have been developed. The transition metal-free and oxidant-free reaction provides a practical and efficient approach for the selective synthesis of methylsulfonyl oxazoles in moderate to excellent yields with good functional group compatibility.

Ni-Catalyzed Reductive Fluoroalkylacylation of Alkynes for the Steroselective Synthesis of Fluoroalkylated Enones.

A Ni-catalyzed three-component reductive fluoroalkylacylation of alkynes with fluoroalkyl halides and acyl chlorides is presented. This dicarbofunctionalization provides an efficient method for the synthesis of fluoroalkyl-incorporated enones under mild conditions with high yields and excellent regioselectivity and stereoselectivity.

Ni-Catalyzed Reductive Arylalkenylation of Alkynes for the Selective Synthesis of Polysubstituted Naphthalenes.

A Ni-catalyzed reductive arylalkenylation of alkynes with 1-bromo-2-(2-chlorovinyl)arenes in the presence of zinc powder has been developed. This base-free cyclization provides a novel protocol for the selective synthesis of 2-trifluoromethyl naphthalenes and ethyl 2-naphthoates from simple starting materials in moderate to good yields with excellent tolerance of functional groups.

Palladium-Catalyzed Methylsulfonylation of Alkyl Halides Using Dimethyl Sulfite as SO2 Surrogate and Methyl Source.

A novel and efficient method for the synthesis of methyl sulfone derivatives via palladium-catalyzed methylsulfonylation of alkyl halides with dimethyl sulfite has been described. A variety of aryl and alkyl iodides underwent the sulfonylation smoothly to furnish methyl sulfites in moderate to excellent yields.

Base-promoted thioannulation of o-alkynyl oxime ethers with sodium sulfide for the general synthesis of isothiocoumarins.

A general and efficient strategy for the one-pot synthesis of isothiocoumarin-1-ones has been developed via the base-promoted 6-endo-dig thioannulation of o-alkynyl oxime ethers using the cheap and readily available Na2S as the sulfur source. Mechanistic studies disclosed that the reaction proceeded through two C-S bond formations, N-O bond cleavage and the final hydrolysis of imines.

A palladium-catalyzed ring-expansion reaction of cyclobutanols with 2-haloanilines leading to benzazepines and quinolines.

A general synthesis of 2-aryl benzazepines has been developed through palladium-catalyzed ring-expansion reactions of cyclobutanols with 2-haloanilines; the further oxidative rearrangement reaction of benzazepines provided an efficient synthesis of 2-acyl quinolines. These transformations feature the efficient construction of six- and seven-membered N-containing heterocycles from easily obtained materials with excellent functional group tolerance.

Iodine-promoted ring-opening methylation of benzothiazoles with dimethyl sulfite.

A halogen-bond promoted ring-opening methylation of benzothiazoles has been developed using dimethyl sulphite as a methylating reagent in the presence of a base. This approach represents a simple and efficient synthesis of N-methyl-N-(o-methylthio)phenyl amides, and features direct construction of both N-Me and S-Me bonds in a one-pot reaction through the decomposition of easily prepared benzothiazoles.

Copper-Catalyzed Selective Defluorinative Sulfuration of Trifluoropropanamides Leading to α-Fluorothioacrylamides.

A practical and efficient method for the synthesis of α-fluorothioacrylamide was developed from selective defluorinative sulfuration of trifluoropropanamides with disulfides. The N-chelation-assisted copper-catalyzed defluorination and sulfurization reactions feature excellent functional group tolerance and incorporation of both sulfur atoms of disulfides into acrylamides.

Synthesis of Isoselenazoles and Isothiazoles from Demethoxylative Cycloaddition of Alkynyl Oxime Ethers.

A general method for the synthesis of isoselenazoles and isothiazoles has been developed by the base-promoted demethoxylative cycloaddition of alkynyl oxime ethers using the cheap and inactive Se powder and Na2S as selenium and sulfur sources. This transformation features the direct construction of N-, Se-, and S-containing heterocycles through the formation of N-Se/S and C-Se/S bonds in one-pot reactions with excellent functional group tolerance.

DBU-Promoted Demethoxylative Thioannulation of Alkynyl Oxime Ethers with Sulfur for the Synthesis of Bisisothiazole-4-yl Disulfides.

An efficient synthesis of bisisothiazole-4-yl disulfides via the demethoxylative thioannulation of alkynyl oxime ethers with odorless elemental sulfur has been first developed. This transformation involves the N-O bond cleavage, the formation of multiple C-S and N-S bonds, providing an efficient way for constructions of both isothiazoles and disulfides. Straightforward elaboration of the products to isothiazole thioethers expands the synthetic utility of this reaction.

Copper-Catalyzed Electrophilic Cyclization of N-Propargylamines with Sodium Sulfinate for the Synthesis of 3-Sulfonated Quinolines.

A convenient and effective protocol for the synthesis of 3-sulfonated quinolines via copper-catalyzed electrophilic cyclization of N-propargylamines has been developed, in which cheap and stable sodium sulfinates were utilized as green sulfonylation reagents. This cascade transformation involves radical addition, cyclization and dehydrogenative aromatization processes in a one-pot reaction under mild conditions.

Copper-Catalyzed Tandem Sulfuration/Annulation of Propargylamines with Sulfur via C-N Bond Cleavage.

Copper-catalyzed aerobic oxidative sulfuration and annulation of propargylamines with elemental sulfur is described. The tandem reaction involves C-N bond cleavage and the formation of multiple C-S bonds, affording 1,2-dithiole-3-thiones in good to excellent yields with good functional group tolerance.

Organophosphine-free copper-catalyzed isothiocyanation of amines with sodium bromodifluoroacetate and sulfur.

A copper-catalyzed isothiocyanation of amines with sodium bromodifluoroacetate and sulfur in the absence of organophosphine has been established. This approach represents a simple and efficient one-pot synthesis of isothiocyanates, and features excellent functional group tolerance and the use of a cheap, safe and odorless sulfur source. Moreover, this process could directly provide isothiocyanate analogous bioactive molecules, thiocarbonyl-containing pesticides and facile construction of benzoxazole and benzimidazole frames.

Ni-Catalyzed Defluorination for the Synthesis of gem-Difluoro-1,3-dienes and Their [4 + 2] Cycloaddition Reaction.

A nickel-catalyzed defluorination of α-trifluoromethylated allyl/propargyl carbonates using bis(pinacolato)diboron (B2pin2) as a reactant is described. The reaction proceeds under relatively mild reaction conditions, providing conjugated gem-difluoroalkenes in moderate to good yields. Applications of the resulting 1,1-difluoro-1,3-dienes by [4 + 2] cycloaddition reactions with maleimide led to cyclic fluorinated products efficiently.

Palladium-Catalyzed Tandem Carbocyclization and Hetroarylation for the Synthesis of 2-(Trifluoromethyl)indenylmethyleneindoles.

A palladium-catalyzed tandem cyclization and cross-coupling reaction of o-(2-chlorovinyl)alkynylbenzenes with indoles/pyrroles is developed. The process proceeds via intramolecular carbocyclization and subsequent hetroarylation to afford previously unknown trifluoromethyl-containing indenylmethyleneindoles, which are potentially useful in drug design.

Copper-Catalyzed N-Formylation of Amines through Tandem Amination/Hydrolysis/Decarboxylation Reaction of Ethyl Bromodifluoroacetate.

Ethyl bromodifluoroacetate (BrCF2COOEt) was first used as the N-formylating reagent in the copper-catalyzed N-formylation of amines. A range of primary, secondary, cyclic arylamines, and aliphatic amines underwent the N-formylation smoothly to furnish the N-formamides in moderate-to-excellent yields.

[Improved anatomical locking plate internal fixation through tarsal sinus incision in treating Sanders III-IV calcaneal fractures].

OBJECTIVE: To investigate clinical effects of improved anatomical locking plate internal fixation through tarsal sinus incision in treating Sanders III and IV calcaneal fractures. METHODS: From February 2015 to October 2016, 35 patients with Sanders III and IV calcaneal fractures treated by improved anatomical locking plate internal fixation through tarsal sinus incision were collected, including 22 males and 13 females aged from 22 to 68 years old with an average of (42.3±12.7) years old. According to Sanders classification, 23 patients were type III and 12 patients were type IV. Postoperative complications were observed, Bö hler angle and Gissane angle before and after operation were compared, and Maryland foot function scoring standard was evaluated at 12 months after operation. RESULTS: All patients were followed up from 12 to 20 months with an average of (14.5±2.0) months, the length of incision ranged from 4.0 to 5.5 cm with an average of (4.7±0.4) cm. Superficial infection occurred in 1 patient, delayed union in 2 patients, gastrocnemius nerve injury in 1 patient. No complications such as steel plate exposure and fracture reduction loss occurred. Wound healing time ranged from 14 to 28 days with an average of(15.4±4.7) days, the fracture healing time ranged from 8 to 14 weeks with an average of (9.8±1.9) weeks. Bö hler angle increased from preoperative (9.81±14.28)° to 3 days after operation (26.35±11.04)°, and (25.96±10.79)° at 12 months after operation(P<0.05). Gissane angle ranged from preoperative (122.54±16.79)° to 3 days after operation (120.85±11.88)°, and (120.62±11.44)° at 12 months after operation and had statistical meaning. Maryland score increased from 12.66±4.10 before operation to 92.20 ±7.82 at 12 months after operation, and 32 patients got excellent results, 2 good and 1 moderate. CONCLUSIONS: Improved anatomical locking plate internal fixation through tarsal sinus incision in treating Sanders III and IV calcaneal fractures, which has advantages of less incision, less soft tissue injury, better fracture reduction and fixation, could receive good reduction and fixation. It is an effective method for Sanders III and IV fracture of calcaneus fracture.