Diversified Synthesis of Chiral Fluorinated Cyclobutane Derivatives Enabled by Regio- and Enantioselective Hydroboration.

The diversified synthesis of chiral fluorinated cyclobutane derivatives has remained a difficult task in synthetic chemistry. Herein, we present an approach for asymmetric hydroboration and formal hydrodefluorination of gem-difluorinated cyclobutenes through rhodium catalysis, providing chiral gem-difluorinated α-boryl cyclobutanes and monofluorinated cyclobutenes with excellent regio- and enantioselectivity, respectively. The key to the success of the two transformations relies on an efficient, mild and highly selective rhodium-catalyzed asymmetric hydroboration with HBPin (pinacolborane), in which the subsequent addition of a base, and a catalytic amount of palladium in some cases, results in the formation of formal hydrodefluorination products with the four-membered ring retained. The obtained chiral gem-difluorinated α-boryl cyclobutanes are versatile building blocks that provide a platform for the synthesis of enantioenriched fluorinated cyclobutane derivatives to a great diversity.

An efficient Selectfluor-mediated condensation of indoles and anthranilates for the synthesis of indoloquinazolinones.

Intermolecular fluorocyclization of indoles with anthranilates, which proceeded smoothly to give diverse indoloquinazolinone architectures under mild reaction conditions, has been developed. A wide range of substrates were compatible with this cyclization system. The synthetic fluorinated compounds could be modified by their conversion to various substituted quinazolinones for drug discovery. In addition, this protocol has been applied to the concise total synthesis of bioactive natural alkaloids phaitanthrins A-B, cephalanthrin A and cruciferane.

The dynamic behavior and intrinsic mechanism of CO2 absorption by amino acid ionic liquids.

Reducing carbon dioxide emissions is one of the possible solutions to prevent global climate change, which is urgently needed for the sustainable development of our society. In this work, easily available, biodegradable amino acid ionic liquids (AAILs) with great potential for CO2 absorption in the manned closed space such as spacecraft, submarines and other manned devices are used as the basic material. Molecular dynamics simulations and ab initio calculations were performed for 12 AAILs ([P4444][X] and [P66614][X], [X] = X = [GLy]-, [Im]-, [Pro]-, [Suc]-, [Lys]-, [Asp]2-), and the dynamic characteristics and the internal mechanism of AAILs to improve CO2 absorption capacity were clarified. Based on structural analysis and the analysis of interaction energy including van der Waals and electrostatic interaction energy, it was revealed that the anion of ionic liquids dominates the interaction between CO2 and AAILs. At the same time, the CO2 absorption capacity of AAILs increases in the order [Asp]2- < [Suc]- < [Lys]- < [Pro]- < [Im]- < [Gly]-. Meanwhile, the synergistic absorption of CO2 by multiple-sites of amino and carboxyl groups in the anion was proved by DFT calculations. These findings show that the anion of AAILs can be an effective factor to regulate the CO2 absorption process, which can also provide guidance for the rational and targeted molecular design of AAILs for CO2 capture, especially in the manned closed space.