Mechanism of a novel metal-free carbonic anhydrase.

The recently discovered metal-free carbonic anhydrase (CA) enzyme may significantly impact the global carbon dioxide (CO) cycle, as it can irreversibly perform the CO hydration reaction. In this study, we investigated several key aspects of metal-free CA, including the identification of the catalytic site, the determination of the CO binding site, and the mechanism of catalysis. This is achieved through classical molecular dynamics (MD) simulations, quantum chemical density functional theory (DFT), and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations.

Regioselective Synthesis of the Tetrahydrocarbazole Core of Alkaloids via Palladium-Catalyzed Intramolecular Arylation Reaction.

Tetrahydrocarbazole is the central core for several biologically active alkaloids, and regioselective synthesis of this core is a challenging task. Herein, we report an efficient strategy for the synthesis of this core involving palladium-catalyzed intramolecular arylation reaction with excellent regioselectivity (>99%) starting from -phenyl-bromoalkene without having any relocation of double bonds via competitive palladium-catalyzed isomerization reaction. Broad functional group tolerance and exclusive regioselectivity have been observed for meta-substituted halide substrates.