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Keywords: phosphine; cyclization; coumarin; furanone EN phosphine cyclization coumarin furanone 1587 1592 6 07/31/23 20230815 NES 230815 Graph Furan and tetrahydrofuran heterocycles are distributed widely in nature, and they are also prevalent building blocks in a vast array of pharmaceutically active molecules (Figure 1). [116] Otherwise, coumarin-fused bicyclo[3.2.0]heptenones will be produced via a phosphine-promoted tandem [3+2] cyclization/intramolecular Wittig cyclization performing the reaction in toluene or THF, which has been disclosed in our previous study. [96] Very recently, coumarin-fused cyclopentanones were selectively afforded in moderate to good yields with excellent diastereoselectivities under phosphine catalysis of 3-benzoyl coumarin with alkynone (Scheme 1c). [95] Followed by that, we then discovered an efficient method for the synthesis of coumarin-fused bicyclo[3.2.0]heptenones via phosphine-promoted tandem [3+2] cyclization/intramolecular Wittig cyclization from 3-aroylcoumarin and alkynone (Scheme 1b). [Extracted from the article]

This study investigates the potential of permeable crystalline materials to improve the properties of recycled aggregates and recycled aggregate concrete (RAC). The use of recycled aggregates in concrete production has gained increasing attention due to environmental and economic benefits. However, the lower quality and poorer durability of recycled aggregates limit their wider application. In this study, three types of recycled aggregates were treated with permeable crystalline materials, and their water absorption and crushing index were compared before and after modification. RAC was then produced using modified recycled aggregates with different substitution rates, and their mechanical properties were evaluated. To investigate the mechanism of permeable crystalline materials modification, the microstructure of the modified RAC was observed using nuclear magnetic resonance and scanning electron microscopy. The results demonstrated that the permeable crystalline materials treatment effectively reduced the water absorption and crushing index of the recycled aggregates. The compressive strength of modified RAC also improved, with a higher modification time leading to higher strength. Furthermore, the pore distribution and microstructural denseness of the modified recycled aggregates and RAC were enhanced, as revealed by the microstructural observations. These findings suggest that permeable crystalline materials modification is a promising method for improving the properties of recycled aggregates and RAC, which could contribute to the sustainable development of the construction industry. [ABSTRACT FROM AUTHOR]

A phosphine-promoted intermolecular annulation reaction of functionalized 3-benzoyl coumarin with alkynone has been disclosed. This reaction was found to be highly dependent on the nucleophilicity of the phosphine. Two classes of coumarin-fused cyclopentanones were selectively afforded in moderate to good yields with excellent diastereoselectivities under the mild reaction conditions. [ABSTRACT FROM AUTHOR]

This paper studies a guidance and control framework of multiple autonomous surface underwater vehicles (multi-ASUV) based on deep reinforcement learning (DRL) for target tracking. The framework enables the vehicles to complete the standoff tracking and sampling tasks in a predetermined circular trajectory centered on the target and maintain predetermined relative positions during the process to obtain high-precision spatio-temporal synchronization data. We design an end-to-end architecture that maps the sensor inputs to control commands and develop autonomous capable of achieving the hybrid objective of cooperative guidance, standoff tracking, and dynamic obstacle avoidance without having prior knowledge about the goal or the environment. The results demonstrate the feasibility of the end-to-end DRL method with higher accuracy than the traditional "guidance-control" two-step method. Meanwhile, the obstacle avoidance and standoff tracking experiment for swarm and the sampling experiment in the mesoscale eddy area are stimulated further to verify the proposed framework's effectiveness and robust ability. • We propose a Deep-Reinforcement-Learning-based Multi-vehicle Cooperative Standoff Tracking Framework. • Through end-to-end control, each vehicle eventually converges to the tracking circle and distributes evenly. • This paper solve the difficult-to-eliminate uncertainty and delay caused by the combination of "guidance-control" two steps method. [ABSTRACT FROM AUTHOR]

Increased performance of invasive plant species in their introduced range vs. their native range has been previously documented. However, performance differences among invasive populations have rarely been explored, despite this information being central to understanding the evolution of invasiveness as well as being a useful basis to inform management of invasive species. To examine variation in performance among populations of Rosa rugosa in its introduced range, and whether introduced populations perform better than native populations, we quantified growth and reproductive traits in five invasive populations in northwest Europe and two native and declining populations in China. Overall, we found that the introduced R. rugosa populations we sampled performed significantly better than the sampled native populations for growth and reproductive traits (2 to 4 fold increase). However, there was significant variation for most traits among the five invasive populations, demonstrating that some introduced populations we sampled were more successful invaders than others. Our findings provide a useful foundation for management of invasive R. rugosa in Europe, and support the recent call for more intra-species research in invasive species biology.