The synthesis of unsymmetrical push–pull benzoporphyrins has been realized. UV-Vis and fluorescence spectroscopy, cyclic voltammetry and DFT calculations reveal subtle substituent effects on the electronic and optical properties of these porphyrins.

Inhibition of the signaling pathways of signal transducer and activator of transcription 3 (STAT 3) has shown to be a promising strategy to combat cancer. In this paper we report the design, synthesis and evaluation of a novel class of small molecule inhibitors, that is, XZH-5 and its analogues, as promising leads for further development of STAT3 inhibitors. Preliminary SARs was established for XZH-5 and its derivatives; and the binding modes were predicted by molecular docking. Lead compounds with IC50 as low as 6.5 μM in breast cancer cell lines and 7.6 μM in pancreatic cancer cell lines were identified.

The synthesis of a series of β-functionalized push–pull dibenzoporphyrins was realized. These porphyrins display subtle push–pull effects, demonstrating the exceptional tunability of their electronic and electrochemical properties. The UV–vis spectra of these porphyrins show unique absorption patterns with shouldered Soret bands and extra absorptions in the Q-band region. Stronger electron-withdrawing groups display more significant bathochromic shifts of the Soret bands. The fluorescence spectra of these porphyrins show strong near-IR emission bands (600–850 nm). In particular, fluorescence quenching effect was observed for pyridyl carrying push–pull porphyrin 4c in the presence of an acid. TFA titration study of 4c using UV–vis and fluorescence spectroscopy reveals that the fluorescence quenching can be mainly attributed to the protonation of the pyridyl groups of 4c. The versatile synthetic methods developed in this work may open a door to access a large number of functionalized organic materials that are currently unavailable. The structure–property studies provided in this work may provide useful guidelines for the design of new generations of materials in dye-sensitized solar cells, in nonlinear optical applications, as fluorescence probes, as well as sensitizers for photodynamic therapy.

A new type of chiral bimetallic catalyst is disclosed. These chiral bimetallic catalysts are easily formed through mixing a metal Lewis acid and a metal binaphthyl phosphate (MLA/M[P]3) in solution. 1H and 31P NMR spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and X-ray crystallographic analysis reveal a bimetallic structure of the Y(Yb)III/Y[P]3 complexes with bridging binaphthyl phosphate ligands. The Lewis acidity of these chiral bimetallic catalysts is readily tuned by changing either the metal Lewis acid or the chiral metal phosphate. Through cooperative metal Lewis acid–enamine catalysis, asymmetric three-component aza-Diels–Alder reactions of 5-, 6-, and 7-membered cyclic ketones, unsaturated ketoesters, and arylamines were successfully achieved to afford fused bicyclic dihydropyridines in high yields (up to 94%) with high enantioselectivity (up to 99% enantiomeric excess) and excellent chemoselectivity.

Synergistic–cooperative combination of enamine catalysis with transition metal catalysis is an emerging and exciting field aiming to achieve organic transformations that cannot be accomplished by individual catalysis. The biggest obstacle in this field lies in the catalyst incompatibility arising from Lewis acid–Lewis base interactions. Several strategies including soft/hard combination of a Lewis acid and a Lewis base, the utilization of a chelating ligand, and mixing an ammonium salt with a Lewis acid have been developed to solve the incompatibility problem. A number of new reactions and new reaction modes have been discovered using these strategies. In this review article, we aim to highlight these new discoveries found in the literature.

A Sc(OTf)3-catalyzed three-component cyclization reaction of arylamines, β,γ-unsaturated α-ketoesters and 1,3-dicarbonyl compounds was developed to synthesize highly substituted 1,4-dihydropyridines and fused bicyclic tetrahydropyridines carrying a quaternary all-carbon center.

Synergistic–cooperative combination of enamine catalysis with transition metal catalysis is an emerging and exciting field aiming to achieve organic transformations that cannot be accomplished by individual catalysis. The biggest obstacle in this field lies in the catalyst incompatibility arising from Lewis acid–Lewis base interactions. Several strategies including soft/hard combination of a Lewis acid and a Lewis base, the utilization of a chelating ligand, and mixing an ammonium salt with a Lewis acid have been developed to solve the incompatibility problem. A number of new reactions and new reaction modes have been discovered using these strategies. In this review article, we aim to highlight these new discoveries found in the literature.