Zinc-catalyzed [4+3] cycloaddition with concomitant furan annulation: formation of cyclohepta[b]furans.

A convenient zinc-promoted [4+3] cycloaddition of a carbonyl ene-yne with simple dienes was first achieved. This reaction provided an efficient strategy to prepare various cyclohepta[b]furan rings by cascade cycloadditions. Additionally, a multicomponent reaction of dione, alkynal, and diene was also reported, which exhibited a novel strategy for selective creations of C-O bonds and C-C bonds.

Intercomparison of measured and modelled photochemical ozone production rates: Suggestion of chemistry hypothesis regarding unmeasured VOCs.

Ozone (O3) pollution is a severe environmental problem in China. The incomplete understanding of atmospheric photochemical reaction mechanisms prevents us from accurately understanding the chemistry of O3 production. Here, we used an improved dual-channel reaction chamber technique to measure net photochemical O3 production rate (P(O3)net) directly in Dongguan, a typical industrial city in China. The maximum P(O3)net was 46.3 ppbv h-1 during the observation period, which is at a relatively high level compared to previous observations under different environment worldwide. We employed an observation-based box model coupled with the state-of-the-art atmospheric chemical mechanism (MCM v3.3.1) to investigate the chemistry of O3 production. Under the base scenario, the modelling underestimates P(O3)net by ~30 %. Additionally considering HO2 uptake by ambient aerosols, inorganic deposition, and Cl chemistry only caused a small change (< 13 %) in the simulation of P(O3)net. Further analysis indicates that unmeasured reactive volatile organic compounds (VOCs), such as oxygenated VOCs and branched alkenes are potential contributors to the underestimation of P(O3)net. This study underscores the underestimation of P(O3)net in conventional atmospheric modelling setups, providing a crucial scientific foundation for further investigation aimed at promoting our understanding of photochemical O3 formation.

Brønsted acid catalyzed and NIS-promoted cyclization of diynones: selective synthesis of 4-pyrone, 4-pyridone, and 3-pyrrolone derivatives.

Brønsted acid catalyzed tandem cyclization was found to be highly effective for the preparation of a series of polysubstituted 4-pyrones from diynones (yield up to 99%). 4-Pyridone and 3-pyrrolone derivatives were also selectively synthesized by employing NIS and/or Brønsted acid. NIS as an electrophilic reagent could promote these reactions efficiently and rapidly under very mild reaction conditions.

Bi(III)-catalyzed intermolecular reactions of (Z)-pent-2-en-4-yl acetates with ethynylarenes for the construction of multisubstituted fluorene skeletons through a cascade electrophilic addition/cycloisomerization sequence.

A Bi(III)-catalyzed method for the synthesis of highly conjugated aromatic multisubstituted fluorene with (Z)-pent-2-en-4-yl acetates and ethynylarenes via domino reaction is described. In this process, the reaction appears to be very general and suitable for a variety of multisubstituted fluorene.

Synthesis of tetrasubstituted cyclopentadienes via palladium-catalyzed reaction of (Z)-2-en-4-yn acetates and N-methyl indoles.

An efficient approach for the synthesis of tetrasubstituted cyclopentadienes through Pd-catalyzed reactions of (Z)-2-en-4-yn acetates with substituted indoles was developed. This methodology has the advantages of broad scope, simple conditions and easily accessible starting materials.

One pot synthesis of indene through copper(I)-catalyzed three-components coupling and cyclization reaction.

A new and efficient synthesis of substituted indene has been achieved via copper(I)-catalyzed domino three-component coupling and cyclization reaction in moderate to good yield.

Copper-catalyzed dimerization fragmentation cyclization reactions of (E)-1-en-4-yn-3-ols as a versatile approach for the synthesis of multisubstituted 1H-cyclopenta[b]naphthalenes.

An intermolecular condensation reaction of 1,3,5-triarylenynols catalyzed by copper is developed. This reaction is a straightforward method for the synthesis of highly conjugated 1H-cyclopenta[b]naphthalene. Fluorescent properties have been determined for some of the products.

Facile synthesis of halogenated spiroketals via a tandem iodocyclization.

A strategy for the synthesis of spiroketal compounds through a tandem iodocyclization of 1-(2-ethynylphenyl)-4-hydroxybut-2-yn-1-one derivatives is presented. This reaction could proceed under very mild conditions in a short time and avoid the use of expensive and toxic metal catalysts. Moreover, the resulting halides can be further exploited by subsequent palladium-catalyzed coupling reactions, which act as the important intermediates for building other valuable compounds.

Palladium-catalyzed insertion of α,ß-unsaturated N-tosylhydrazones and trapping with carbon nucleophiles.

Palladium-catalyzed carbene migratory insertion-cyclization reactions were reported, delivering dihydronaphthalene and indene derivatives in moderate to good yields. A three-component cross-coupling was also developed. The reactions are easy to handle, under mild conditions and various functional groups are tolerated.

Facile synthesis of 2-iodo-spiro[indene-1,1'-isobenzofuran]-3'-ones via iodine-promoted cascade cyclization.

A novel and efficient synthetic approach to substituted 2-iodo-spiro[indene-1,1'-isobenzofuran]-3'-ones has been developed via an iodine-promoted cascade cyclization of 2-(3-hydroxy-3,3-diarylprop-1-yn-1-yl)benzoates. This sequential cascade process is concisely conducted at room temperature. Subsequent palladium-catalyzed Sonogashira, Suzuki, and Heck reactions of the resulting iodides proceed smoothly in good yields.