COVID-19, Anti-Intellectualism, and Health Communication: Assessing the Chinese Social Media Platform Sina Weibo.

In the digital media era, new media platforms have become the main channels for transmitting medical and health information in China. However, anti-intellectualism limits the effectiveness of disseminating health information. Therefore, in China, the government and health departments have made efforts to determine how to control anti-intellectualism to effectively disseminate medical and health information, given the situation of a global pandemic and its counter-measures. Against this backdrop, this study applied textual analysis to explore the manifestations of anti-intellectualism in network platforms. The key findings indicate that the irrational behavior of anti-intellectuals is manifested in emotional dominance, abusive behavior, overconfidence and trusting rumors. Based on these results, the authors propose some measures to balance the relationship between anti-intellectualism and health communication. The findings of the study have significant implications for improving the effectiveness of health communication in China.

Scalable Preparation of 4,4-Disubstituted Six-Membered Cyclic Sulfones.

We provide an account of synthetic strategies aimed at the efficient preparation of 4-amino-4-methyltetrahydro-2H-thiopyran 1,1-dioxide (3), an important cyclic sulfone building block for medicinal chemistry. A practical and scalable protocol has been developed that readily gives access to the title compound from commercially available and inexpensive starting materials. In addition, this novel approach has enabled the synthesis of various related 4,4-disubstituted cyclic sulfone derivatives that serve as valuable structural motifs for drug discovery.

Government Communication, Perceptions of COVID-19, and Vaccination Intention: A Multi-Group Comparison in China.

Government communication has been playing an important role in mass vaccination to conduct the largest vaccination campaign of the world for COVID-19 and to counter vaccine hesitancy. This study employs the health belief model to examine the association between government communication and the COVID-19 vaccination intention. A survey of Chinese adults (N = 557) was conducted in March 2021, and partial least squares structural equation modeling was employed to estimate the multi-construct relationships. The findings indicate that government communication has both direct positive association with vaccination intention and indirect association with vaccination intention through the mediation of perceived severity, benefits, and barriers. Multi-group comparisons suggest that individuals from private sectors are more easily mobilized to receive COVID-19 vaccination by government communication than those from public sectors. Similarly, the correlation between government communication and the vaccination intention of individuals with a good health status was stronger than that of those with a poor health status. The theoretical and practical implications of these findings are further discussed.

A dual-catalysis approach to enantioselective [2 + 2] photocycloadditions using visible light.

In contrast to the wealth of catalytic systems that are available to control the stereochemistry of thermally promoted cycloadditions, few similarly effective methods exist for the stereocontrol of photochemical cycloadditions. A major unsolved challenge in the design of enantioselective catalytic photocycloaddition reactions has been the difficulty of controlling racemic background reactions that occur by direct photoexcitation of substrates while unbound to catalyst. Here, we describe a strategy for eliminating the racemic background reaction in asymmetric [2 + 2] photocycloadditions of α,ß-unsaturated ketones to the corresponding cyclobutanes by using a dual-catalyst system consisting of a visible light-absorbing transition-metal photocatalyst and a stereocontrolling Lewis acid cocatalyst. The independence of these two catalysts enables broader scope, greater stereochemical flexibility, and better efficiency than previously reported methods for enantioselective photochemical cycloadditions.

Photocatalytic Reductive Cyclizations of Enones: Divergent Reactivity of Photogenerated Radical and Radical Anion Intermediates.

Photocatalytic reactions of enones using metal polypyridyl complexes proceed by very different reaction manifolds in the presence of either Lewis or Brønsted acid additives. Previous work from our lab demonstrated that photocatalytic [2+2] cycloadditions of enones required the presence of a Lewis acidic co-catalyst, presumably to activate the enone and stabilize the key radical anion intermediate. On the other hand, Brønsted acid activators alter this reactivity and instead promote reductive cyclization reactions of a variety of aryl and aliphatic enones via a neutral radical intermediate. These two distinct reactive intermediates give rise to transformations differing in the connectivity, stereochemistry, and oxidation state of their products. In addition, this reductive coupling method introduces a novel approach to the tin-free generation of ß-ketoradicals that react with high diastereoselectivity and with the high functional group compatibility typical of radical cyclization reactions.

Visible light photocatalysis as a greener approach to photochemical synthesis.

Light can be considered an ideal reagent for environmentally friendly, 'green' chemical synthesis; unlike many conventional reagents, light is non-toxic, generates no waste, and can be obtained from renewable sources. Nevertheless, the need for high-energy ultraviolet radiation in most organic photochemical processes has limited both the practicality and environmental benefits of photochemical synthesis on industrially relevant scales. This perspective describes recent approaches to the use of metal polypyridyl photocatalysts in synthetic organic transformations. Given the remarkable photophysical properties of these complexes, these new transformations, which use Ru(bpy)(3)(2+) and related photocatalysts, can be conducted using almost any source of visible light, including both store-bought fluorescent light bulbs and ambient sunlight. Transition metal photocatalysis thus represents a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.

Anionic halocuprate(II) complexes as catalysts for the oxaziridine-mediated aminohydroxylation of olefins.

We have discovered that the oxaziridine-mediated copper-catalyzed aminohydroxylation reaction recently discovered in our laboratories is dramatically accelerated in the presence of halide additives. The use of this more active catalyst system enables the efficient aminohydroxylation of electronically and sterically deactivated styrenes and also enables the use of nonstereogenic 3,3-dialkyl oxaziridines as terminal oxidants in the aminohydroxylation reaction. We present evidence that anionic halocuprate(II) complexes are the catalytically active species responsible for the increased reactivity under these conditions. This unexpected observation has led us to re-evaluate our mechanistic understanding of this reaction. On the basis of the results of a variety of radical trapping experiments, we propose a modified mechanism that involves a homolytic reaction of the olefin with a copper(II)-activated oxaziridine. Together, the observation that anionic additives significantly increase the oxidizing ability of oxaziridines and the recognition of the radical nature of reactions of oxaziridines under these conditions suggest that a variety of new oxidative transformations catalyzed by halocuprate(II) complexes should be possible.

Crossed intermolecular [2+2] cycloadditions of acyclic enones via visible light photocatalysis.

Efficient [2+2] heterodimerizations of dissimilar acyclic enones can be accomplished upon visible light irradiation in the presence of a ruthenium(II) photocatalyst. Similar cycloadditions under standard UV photolysis conditions are inefficient and unselective. Nevertheless, a diverse range of unsymmetrical tri- and tetrasubstituted cyclobutane structures can be produced in good yields and excellent diastereoselectivities using this new method. The reaction is promoted by any visible light source, and efficient, gram-scale cycloadditions can be conducted upon irradiating with ambient sunlight.

Efficient visible light photocatalysis of [2+2] enone cycloadditions.

We report that Ru(bipy)3Cl2 can serve as a visible light photocatalyst for [2+2] enone cycloadditions. A variety of aryl enones participate readily in the reaction, and the diastereoselectivity in the formation of the cyclobutane products is excellent. We propose a mechanism in which a photogenerated Ru(bipy)3+ complex promotes one-electron reduction of the enone substrate, which undergoes subsequent radical anion cycloaddition. The efficiency of this process is extremely high, which allows rapid, high-yielding [2+2] cyclizations to be conducted using incident sunlight as the only source of irradiation.