PtCl2-Catalyzed Cycloisomerization of 1,8-Enynes: Synthesis of Tetrahydropyridine Species

Photocatalyzed Cascade Hydrogen Atom Transfers for Assembly of Multi-Substituted α-SCF3 and α-SCF2H Cyclopentanones

A photocatalyzed formal (3+2) cycloaddition has been developed to construct original polysubstituted α-SCF3 cyclopentanones in a regio- and diastereoselective manner. This building block approach leverages trifluoromethylthio alkynes and branched/linear aldehydes, as readily available reaction partners, in consecutive hydrogen atom transfers and C-C bond formations. Difluoromethylthio alkynes are also compatible substrates. Furthermore, the potential for telescoped reaction starting from alcohols instead of aldehydes was demonstrated, as well as process automatization and scale-up under continuous microflow conditions. This prompted density functional theory (DFT) calculations to support a radical-mediated cascade process.

Computational analysis of the formation mechanisms of carbazoles

Gold-, platinum-, and silver-catalyzed formation mechanisms of carbazole alkaloids were investigated computationally. The structural properties of the reactants were studied in various solvents and with different functionals. The hybrid functionals B3LYP and M06-2X in density functional theory were used to determine and discuss the energetics of the compounds. The electronic properties of groups attached to the terminal alkyne played an essential role in the formation of carbazoles. The stereo- and chemoselectivity of the mechanism were investigated and the natural bond orbitals of the reactants were determined. Furthermore, this theoretical study has suggested a gold-catalyzed alternative mechanism for the synthesis of 1,4-dihydrocyclopenta[b]indole derivative.