Boron Trifluoride Etherate Promoted Regioselective 3-Acylation of Indoles with Anhydrides

An efficient, high-yielding and scalable procedure for the regioselective 3-acylation of indoles with anhydrides promoted by boron trifluoride etherate under mild conditions was reported. This novel protocol provided a simple way to prepare 3-(benzofuran-2-yl) indole in three steps.

Photo-Thermo-Mechanochemical Approach to Synthesize Quinolines via Addition/Cyclization of Sulfoxonium Ylides with 2-Vinylanilines Catalyzed by Iron(II) Phthalocyanine

A novel photo-thermo-mechanochemical approach to assembling quinolines catalyzed by iron(II) phthalocyanine has been realized for the first time. This transformation features a cost-efficient catalytic system and operational simplicity, is free of solvent, and shows good substrate tolerance, providing a green alternative to existing thermal approaches. Mechanistic experiments demonstrate that the in-situ-formed secondary amine may be the key intermediate for the further cyclization/aromatization process.

Mechanochemical sulfonation of aromatic compounds using NaHSO4·H2O/P2O5

A series of aromatic sulfonic acids is synthesized by subjecting arenes and NaHSO4·H2O to high-speed ball milling in the presence of P2O5. It is suggested the aromatic sulfonation occurs via in situ generated H2SO4 to give aromatic sulfonic acids. In some cases, formation of diaryl sulfones was observed.

A copper-promoted synthesis of epoxy-bridged [60]fullerene-fused lactones and further derivatization

A facile copper-promoted decarboxylative annulation of [60]fullerene (C60) with two identical α-oxocarboxylic acids via an unprecedented cascade addition pathway has been exploited to synthesize the unique epoxy-bridged C60-fused lactones for the first time. Further transformations into the rare epoxy-bridged C60-fused hemiacetals and bicyclic-fused 1,2,3,4-adducts as well as application in a perovskite solar cell device of the obtained products have also been demonstrated. The structures of the epoxy-bridged C60-fused lactones and derived reductive products have been unequivocally established by single-crystal X-ray crystallography. Plausible reaction mechanisms leading to the observed products are proposed.

Two approaches for the synthesis of levo-praziquantel

We report herein the development of two pathways for the preparation of levo-praziquantel (R-PZQ), which involves three-/four-step processes of a mechanochemical (asymmetric) aza-Henry/acylation reaction, a hydrogenation reaction, (chiral resolution) and a solvent-free acylation-ring closing reaction. The key intermediate (R)-1-aminomethyl tetrahydroisoquinoline could be obtained either by chiral resolution with a rational reuse of the S-isomer or by mechanochemical enantioselective synthesis that refrained from using a bulky toxic solvent. The efficiency and scalability of both the developed routes were demonstrated and desired target product was obtained in a satisfactory yield with excellent enantiopurity (>99%), offering practical, concise and environmentally friendly alternatives to access R-PZQ.

A General and Scalable Synthesis of Polysubstituted Indoles

A consecutive 2-step synthesis of N-unprotected polysubstituted indoles bearing an electron-withdrawing group at the C-3 position from readily available nitroarenes is reported. The protocol is based on the [3,3]-sigmatropic rearrangement of N-oxyenamines generated by the DABCO-catalyzed reaction of N-arylhydroxylamines and conjugated terminal alkynes, and delivers indoles endowed with a wide array of substitution patterns and topologies.

Synthesis of 3-acylindoles via copper-mediated oxidative decarbethoxylation of ethyl arylacetates

An efficient regioselective C-3 acylation of free indoles (N-H) has been accomplished via oxidative decarbethoxylation of easily available ethyl arylacetates using Cu(OAc)2 and KOtBu in DMSO.

Photocatalyst-free decarboxylative aminoalkylation of imidazo[1,2-a]pyridines with N-aryl glycines enabled by visible light

A novel, green and efficient visible-light-promoted decarboxylative aminoalkylation reaction of imidazo[1,2-a]pyridines with N-aryl glycines has been described.