Electrophilic Selenium Catalysis with Electrophilic N-F Reagents as the Oxidants.

A suitable oxidative system is crucial to electrophilic selenium catalysis (ESC). This short review offers the overview of recent development in ESC with electrophilic N-F reagents as the oxidants. Several highly selective transformations of alkenes such as allylic or vinylic imidation, pyridination, syn-dichlorination, oxidative cyclization and asymmetric cyclization have been described.

Organoselenium-Catalyzed Regioselective C-H Pyridination of 1,3-Dienes and Alkenes.

An efficient approach for organoselenium-catalyzed regioselective C-H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C-H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C-H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C-H pyridination.

Assessment and analysis of the balance between economic development and ecological environment protection and its implementation strategy derived from spatial planning-Take three heterogeneous and representative provinces in China as an example.

Balancing ecological environment protection (EEP) and economic development (ED) (balance for short) is a difficult problem that must be solved in the development of modern society, particularly important for realizing UN Sustainable Development Goals. How to assess the regional balance situation and reveal the spatial and temporal heterogeneous characteristics of the balance (especially for the vast China) and its influencing factors are the primary scientific problems and realistic needs. Taking Zhejiang, Hunan and Gansu Provinces in the eastern, central and western region of China as a regional representative, an index system characterizing EEP and ED were established, which were processed by extreme difference method and entropy weight method. The coupling characteristics, stress factors and coordination type from 2010 to 2019 in the 3 provinces were assessed and analyzed by means of the coupling coordination model and the grey correlation degree model. Balance is the mission and responsibility of the spatial planning system for spatial planning is of the source, whole-region and comprehensiveness of public strategy, therefore, the balance strategies and its integration approaches are constructed in the 3 provincial spatial planning based on the assessment and analysis of balance characteristics. Research results show that: (1) the 3 provinces' coupling coordination degree is rising year by year, coordination type is more and more better indicating that the balance of EEP and ED is getting better and better, but coordination type differentiates at one level between 3 provinces at the east, central, western region of China, Zhejiang province is from nearby imbalance to primary coordination, Hunan Province is from nearby imbalance to narrow coordination, and Gansu Province is from medium imbalance to nearby imbalance. (2) The ED have same strong stress on EEP in the 3 provinces, and the constraints of EEP on ED are different, the current balance characteristics of Zhejiang, Hunan and Gansu province are the types of ecological environment pressure constraints primary coordination, ecological environment pressure constraints narrow coordination, and ecological environment condition constraints nearby imbalance. (3) The coordination types are the co-environmental pressure constraints primary coordination (Zhejiang Province), eco-environmental pressure constraints narrow coordination (Hunan Province) and eco-environmental condition constraints nearby imbalance (Gansu Province), and corresponding balanced planning strategy system are to promote ecological modernization, implement ecological industrialization and adhere to the ecological fundamentalization.

Organoselenium-Catalyzed Synthesis of Oxygen- and Nitrogen-Containing Heterocycles.

A new and efficient approach for the synthesis of oxygen and nitrogen heterocycles by organoselenium catalysis has been developed. The exo-cyclization proceeded smoothly under mild conditions with good functional group tolerance and excellent regioselectivity. Mechanistic studies revealed that 1-fluoropyridinium triflate is key for oxidative cyclization.