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The first highly enantioselective asymmetric decarboxylative addition of β-keto acids with 3-alkenyl-oxindoles bearing an all-carbon quaternary stereocenter have been developed. The relevant products were acquired in 49-98% yields with 88-98% enantioselectivities in the presence of 0.04-1.0 mol % of chiral rhodium catalyst. The comprehensive practicability of this method was proven in the preparation of the key intermediate, which can be easily transformed into analogues of physovenine and physostigmine.

Direct catalytic asymmetric vinylogous Michael addition to construct an acyclic all-carbon quaternary center with novel 3-alkenyl-oxindoles.

The new coronavirus (COVID-19) has generated an unprecedented degree of social and economic impact on the planet, but few researchers have explored the repercussion of COVID-19 for sustainable development (SD) and corporate social responsibility (CSR), especially from the perspective of Chinese businesses. This paper is the first to outline the priority changes of both SD and CSR over the period of COVID-19 incidence in China. An online questionnaire survey of 1161 owners and managers of Chinese companies was conducted, and respondents were asked to score the priorities of their company over the pre, during and post COVID-19 periods. The research was carried out at the end of the first COVID-19 wave in China but during the period of lockdown in some parts of the country. It was found that there was a priority change regarding three dimensions of sustainable development and 13 aspects of CSR. While the social dimension of SD was prioritized during and post COVID-19, the environmental dimension was the only one deemed to be less important and less prioritized over the longer term after the pandemic. The top three short-term CSR priorities were having in place a workplace health and safety plan, engaging in philanthropic activities and protecting biodiversity, and the top three longer-term CSR priorities were job creation, protecting biodiversity and having in place a workplace health and safety plan. Environmental protection and using clean energy were not reported as a CSR priority. The paper concludes that China's recovery mode cannot be called 'green' and suggests ways this could be changed.

In this paper, a mathematical model is proposed to analyze the dynamic behavior of COVID-19. Based on inter-city networked coupling effects, a fractional-order SEIHDR system with the real-data from 23 January to 18 March, 2020 of COVID-19 is discussed. Meanwhile, hospitalized individuals and the mortality rates of three types of individuals (exposed, infected and hospitalized) are firstly taken into account in the proposed model. And infectivity of individuals during incubation is also considered in this paper. By applying least squares method and predictor-correctors scheme, the numerical solutions of the proposed system in the absence of the inter-city network and with the inter-city network are stimulated by using the real-data from 23 January to $18-m$ March, 2020 where $m$ is equal to the number of prediction days. Compared with integer-order system ($\alpha=0$), the fractional-order model without network is validated to have a better fitting of the data on Beijing, Shanghai, Wuhan, Huanggang and other cities. In contrast to the case without network, the results indicate that the inter-city network system may be not a significant case to virus spreading for China because of the lock down and quarantine measures, however, it may have an impact on cities that have not adopted city closure. Meanwhile, the proposed model better fits the data from 24 February to 31, March in Italy, and the peak number of confirmed people is also predicted by this fraction-order model. Furthermore, the existence and uniqueness of a bounded solution under the initial condition are considered in the proposed system. Afterwards, the basic reproduction number $R_0$ is analyzed and it is found to hold a threshold: the disease-free equilibrium point is locally asymptotically stable when $R_0\le 1$, which provides a theoretical basis for whether COVID-19 will become a pandemic in the future., Comment: 11 pages, 10 figures, ND Special Issue paper submitted

One-step vibrational mixing has afforded the batch-scale preparation of a Janus emulsion. The fabrication of Janus particles (JPs) templated by Janus emulsions was motivated by the topology and composition of the Janus droplets being highly tunable and controllable. Two immiscible polymerizable monomers were introduced as inner phases of the Janus emulsion. The advanced geometry of the resultant JPs was easily and precisely controlled from "snowman" to "dumbbell" by adjusting the mass ratio of two oils in the initial emulsion. The surface coverage of one lobe to the other was tuned by adjusting the mass ratio of mixed surfactants. Moreover, the size of JPs was able to be extended continuously from hundreds of micrometers to a few hundred nanometers while their morphologies remained within this wide size range. The proposed strategy is a universal technique in the synthesis of a family of composite polymeric JPs with both chemical and shape anisotropy. In addition, the as-generated chemically biphasic JPs were applied as emulsifiers to stabilize Pickering emulsions, and more attractively, emulsion inversion was readily achieved by choosing JPs with different morphologies.

Anisotropic particles, with morphology from crescent to moon shape and size from micrometer to nanometer scale, are fabricated in batch scale with Janus emulsion as template. The strategy is also useful in the synthesis of Janus particles with chemically distinct hemispheres.

Droplet topology of a Janus emulsion in a vegetable oil (VO)/silicone oil (SO)/Tween 80 aqueous solution (Aq) system prepared in a one-step high energy mixing was investigated, mainly by image observation. Quantitative information of the topology was analyzed referring to the curvature of VO/SO interface, the location of contact plane, and the volume ratio of VO/SO within individual droplets. The results show that the “stable Janus emulsion” region in the phase map enlarges with surfactant concentration. The average volume ratio of two oil lobes within an individual Janus droplet agrees with the emulsion composition in the “stable Janus emulsion” region, which means that the droplet topology can be controlled by the emulsion preparation process within realistic limits. The volume ratio of VO/SO within individual droplet ranges from about 0.54 to 0.17 in the VO/SO/3 wt% Tween 80(Aq) system, beyond which separate VO and SO droplets are observed. The topology of a Janus droplet is found to be determined by both the contact angle of three liquids in the contact line and the location of the contact plane. The contact angle of the oil cap is determined by the interfacial tension referring to the local equilibrium. The location of the contact plane is the dominant factor determining the volume ratio of two oil lobes. Composition change in the emulsion results in the corresponding tune of the location of contact plane and subsequently, the volume ratio of two oils within Janus droplets.

Janus emulsions of a polymerizable monomer tripropyleneglycol diacrylate (TP) combined with silicone oil (SO) as inner oil phases and Tween 80 aqueous solution as continuous phase are prepared in a one-step high energy mixing process. The dependence of droplet topology on the concentration of surfactant, TP/SO ratio, and the stirring speed during emulsification is investigated. The result shows that the volume ratio of two oils within an individual droplet changes correspondingly to the total composition of emulsion. Increasing the speed of stirring results in a significant reduction in the droplet size, i.e. a five times increase in the stirring speed produces a droplet size reduction from hundreds to a few microns. What is more important, the topology of Janus drops remains similar for the different preparations. These fundamental investigations illustrate the potential for future Janus particle synthesis in batch scale with a controllable particle topology.