Pd-catalyzed C-H functionalizations promoted by transient directing groups remain largely limited to C-H arylation only. Herein, we report a diverse set of ortho-C(sp)-H functionalizations of benzaldehyde substrates using the transient directing group strategy. Without installing any auxiliary directing group, Pd(II)-catalyzed C-H arylation, chlorination, bromination, and Ir(III)-catalyzed amidation, could be achieved on benzaldehyde substrates. The transient directing groups formed in situ via imine linkage can override other coordinating functional groups capable of directing C-H activation or catalyst poisoning, significantly expanding the scope for metal-catalyzed C-H functionalization of benzaldehydes. The utility of this approach is demonstrated through multiple applications, including late-stage diversification of a drug analogue.

No abstract

With progress in China’s industrialization and urbanization, the contradiction of social and economic development with water resource supply–demand and water environmental pollution becomes increasingly prominent. To cope with the dual constraints of resource shortage and environmental regulations, the concept of water resource green efficiency that considers economic, environmental, and ecological factors is highly involved to promote sustainable economic development. The theoretical and practice circle devote to scientific green efficiency assessment of water resources and effective recognition of relevant influencing factors. However, to an extent they neglect social benefits brought by sustainable development and possible influences of industrial restructuring on green efficiency. They also lack concern on green efficiency of water resources in inland arid areas. To offset the disadvantages of existing studies, the philosophy of sustainable development was integrated into the input–output assessment system of green efficiency of water resources, and an assessment model was constructed using the SBM–Tobit (slack-based measure and Tobit) method. Moreover, a case study based on Henan Province, China was carried out. The green efficiencies of water resources in 18 cities of Henan Province during 2011–2018 were calculated. The operation mechanism of relevant influencing factors was discussed, and the methods to improve green efficiency of water resources were determined. Results reveal that the sustainable green efficiency of water resources in Henan Province increased in fluctuation during 2011–2018. The mean green efficiency increased from 0.425 in 2011 to 0.498 in 2018. At present, green efficiency of water resources in Henan Province remains at a low level, with a mean of 0.504. Reducing water consumption intensity and increasing investment to water environmental pollution technologies can promote green efficiency of water resources significantly. Conclusions provide a new method for scientific measurement and green efficiency assessment of water resources in inland arid areas.

Long-term (2000 to 2012) monthly data on communities of phytoplankton, and environmental variables were measured in water collected from Meiliang Bay and Wuli Lake of Tai Lake, China. Redundancy analysis (RDA) was conducted to explore relationships between the phytoplankton communities and environmental variables. Change points for concentrations of nutrients, which serve as early warnings of state shifts in lacustrine ecosystems, were identified using the Threshold Indicator Taxa Analysis (TITAN). The biomass of phytoplankton was positively correlated with the concentrations of total phosphorus (TP), suspended solids (SS), water temperature (WT), and pH but negatively correlated with the N/P ratio (by mass) and Secchi disk depth (SD). Furthermore, TP, rather than other factors, was a controlling factor limiting the primary production of phytoplankton in most of this region. The change points for concentrations of TP controlling the occurrences of sensitive and tolerant taxa were 56.1 and 103.5 μg TP/L, respectively. These results imply that an abrupt change in this lacustrine ecosystem has occurred in most parts of the study area, and the turbid state of this lake can be altered by reducing TP loading. This study provides an alternative ecological method for exploring the production of algal blooms and could advance the understanding of HABs.

No abstract