Asymmetric synthesis of (R)-baclofen and (3S,4S)-tetflupyrolimet via "on water" organocatalytic addition reactions: a tip on catalyst screening.

This work demonstrates asymmetric synthesis of the GABA derivative (R)-baclofen and a new herbicidal mode-of-action inhibitor (3S,4S)-tetflupyrolimet featuring low loading (0.5 mol%) organocatalytic addition reactions of dithiomalonates to nitrostyrenes under "on water" conditions. Importantly, we observed that increasing the hydrophobicity of the catalyst does not guarantee improved catalytic performance under "on water" conditions and the trends in the catalytic efficiency of different HBD catalysts under "on water" conditions (with hydrophobic additives) align more closely with those observed in pure hydrophobic organic solvents. These findings propose a valuable tip for screening organocatalysts in developing asymmetric hydrogen-bonding catalysis under "on water" conditions.

Preliminary Investigation and Analysis of Beachgoers' Awareness of Rip Currents in South China.

Among many coastal hazards, rip currents have gradually become one of the most noticeable hazards. Studies have demonstrated that most drowning accidents at beaches around the world are related to rip currents. In this study, online and field questionnaires were combined for the first time to reveal beachgoers' awareness of rip currents in China from four aspects: demographic characteristics, swimming ability, information about visiting beaches, and knowledge about rip currents. One educational strategy was introduced to the field survey. The results suggest that (i) the proportion of online and field respondents who have heard of "rip currents" and seen warning signs of rip currents is extremely small. This reflects that beachgoers lack awareness of rip current hazards. Thus, China needs to strengthen the safety education of rip current knowledge. (ii) The level of awareness of rip currents can significantly affect the community's ability to identify the location of rip currents and their choice of escape direction. (iii) In the field survey, we implemented an educational strategy as an intervention for respondents, and the accuracy of identifying rip currents and choosing the correct escape route improved by 34% and 46.7%, respectively. This implies that the intervention of educational strategy can significantly deepen beachgoers' awareness of rip currents. It is recommended that more educational strategies about rip current knowledge be implemented on Chinese beaches in the future.

Access to functionalized 2-pyrones through cascade reactions of α-halothioesters involving DBU-derived ammonium ylides.

Facile access to 4-aryl-6-oxycarbonyl-2-pyrones from α-halothioesters with ß,γ-unsaturated α-keto esters is achieved via a DBU-promoted Michael addition/lactonization/elimination cascade reaction. The reaction mechanism is tentatively elucidated by performing control experiments and high-resolution mass spectrometry analysis, which indicates that the cascade sequence may involve DBU-derived ammonium ylides.