Metal-free oxidative cyclization for the one-pot synthesis of benzo[d]imidazo[2,1-b]thiazoles from 2-aminobenzothiazoles and cyclic ketones is described. Elemental sulfur combined with molecular oxygen as the benign co-oxidant was found to be unique and highly effective to promote this transformation without the aid of any metal salts. Various cyclic ketones smoothly reacted with 2-aminobenzothiazoles to give functional benzo[d]imidazo[2,1-b]thiazoles in good to very high yields, which thereby demonstrated the synthetic convergence of this methodology.

Optically pure pseudo-natural products (PNPs), particularly exemplified by azabicyclo[3.3.1]nonane molecules and their analogs provide an attractive platform for structure−activity relationship studies, and also lead new compound discovery in drug development. However, there are currently no examples of guiding catalytic asymmetric strategies available to construct such important PN-scaffolds, thus limiting their broad use. Here, we report a general and modular method for constructing these pseudo-natural N-bridged [3.3.1] ring systems via cascade process by bifunctional phosphonium salt/Lewis acid relay catalysis. A wide variety of substrates bearing an assortment of functional groups (59 examples) are compatible with this protocol. Other features include a [3 + 2] cyclization/ring-opening/Friedel-Crafts cascade pathway, excellent reactivities and stereoselectivities, easily available starting materials, step economy and scalability. The obtained enantioenriched products showed potential of preliminary anticancer activities. Insights gained from our studies are expected to advance general efforts towards the catalytic synthesis of challenging even unprecedented chiral PNPs, offering new opportunities for bioactive small-molecule discovery.

Autonomous localization methods for Unmanned Aerial Vehicles (UAVs) have significant application potential in complex environments. This paper presents a comprehensive survey of UAV localization techniques, focusing on both pure vision-based and sensor-assisted approaches. For pure vision-based localization, the survey emphasizes key technologies for feature descriptor generation, advancements in similarity measurement criteria, and optimized computational strategies. The impact of these technologies on improving computational efficiency and localization accuracy. In the context of sensor-assisted multi-source UAV localization, the applications of filtering-based fusion, optimization-based fusion, and deep learning-based fusion methods are discussed. A detailed analysis demonstrates the advantages of multi-modal data fusion in improving robustness and accuracy. Despite significant progress in localization accuracy and adaptability to complex environments, challenges remain in adapting to low-texture environments, optimizing fusion strategies, and addressing computational resource limitations. Finally, the paper discusses future directions for the research and implementation of UAV autonomous localization methods.

A novel method for the synthesis of α-aminonitrile through visible-light-induced oxidative cyanation of N-aryltetrahydroisoquinoline with potassium thiocyanate has been developed. The process does not require the use of a photocatalyst, transition metal reagent, strong oxidizing agent, or toxic cyano-containing compound, which makes the reaction simple and green.