No abstract

The Cu-catalyzed asymmetric conjugate hydroboration reaction of β-substituted α-dehydroamino acid derivatives has been established, affording enantioenriched syn- and anti-β-boronate-α-amino acid derivatives with excellent combined yields (83-99%, dr ≈ 1:1) and excellent enantioselectivities (92-98% ee). The hydroboration products were expediently converted into valuable β-hydroxy-α-amino acid derivatives, which were widely used in the preparation of chiral drugs and bioactive molecules.

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As a kind of sustainable technology, prefabricated construction has increasingly gained momentum internationally due to its numerous benefits that include, but are not limited to, safe construction, waste minimization, quality improvement, and productivity enhancement. However, productivity in this domain is reliant on the efficiency of both on-site and off-site operations. On this basis, focusing on collaborative scheduling mechanisms, the current paper develops a static scheduling model and a dynamic scheduling model in prefabricated construction, and uses a simulated annealing algorithm (SA) to settle the optimization of operation planning considering delays by risks. The developed models are validated using data from a construction project with multiple suppliers of prefabricated elements. This study contributes to the body of knowledge in prefabricated construction management by streamlining collaborative scheduling in prefabrication. The established models provide construction managers with decision support systems with the aims of minimizing delays and related cost overruns.

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Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

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An arylation/intramolecular conjugate addition of cyclohexadienone-containing 1,6-enynes has been established through initiation by manganese­(I)-catalyzed C–H bond activation. This tandem reaction involved unusual E/Z-isomerized alkenyl-Mn intermediates and proceeded smoothly with high chemoselectivities and perfect atom economy. The cyclization products could be further transformed to various structures. Mechanistic studies suggested that cleavage of the C–H bond was involved in the turnover-limiting step, and a manganese carbene anion intermediate was proposed to explain such an E/Z isomerization process.