RESUMEN
An efficient, tandem one-pot approach to synthesize multisubstituted 2-acylpyrroles from readily prepared N-tosyl triazoles and 2-hydroxymethylallyl carbonates is reported. The reaction proceeds via Rh(II)-catalyzed O-H insertion, [3,3]-sigmatropic rearrangement, Pd(0)-catalyzed oxidative addition, intramolecular cyclization, DBU-promoted E1cB elimination, double bond isomerization, and aromatization, enabling the disconnection and formation of multiple bonds in one reactor. The approach represents a highly regioselective way to access di-, tri-, and tetra-substituted NH pyrroles with high efficiency.
RESUMEN
Transition metal-catalyzed dipolar cycloaddition is one of the most efficient and powerful synthetic strategies to produce diverse heterocycles. In particular, for the construction of oxygen-containing heterocycles, which are valuable structural motifs found in pharmaceuticals and natural compounds, transition metal-catalyzed oxa-dipolar cycloaddition using an oxygen-containing dipole has emerged as a promising method. In recent years, the 1,4-O/C dipole synthons 2-alkylidenetrimethylene carbonate and 2-hydroxymethylallyl carbonate have been developed and successfully applied to palladium-catalyzed oxa-[4 + n] dipolar cycloadditions with diverse dipolarophiles. In this review, we summarize recent advances in palladium-catalyzed oxa-[4 + n] dipolar cycloadditions using 1,4-O/C dipoles including asymmetric catalysis and divergent catalysis toward five- to nine-membered O-heterocycles.
RESUMEN
A Rh(II)-catalyzed furyl carbene N-H insertion reaction involving an N-sp2-hybridized imine is described, which represents an atom-economical route by which to access diarylmethylamine derivatives with high efficiency and broad substrate scope. An unusual reaction mechanism is proposed, in which the rhodium catalyst plays a dual role in facilitating enynone cyclization via activation and enhancement of the nucleophilicity of the NH imine.
RESUMEN
OBJECTIVE: This study evaluated protective behaviors against coronavirus disease-2019 (COVID-19) and related factors in individuals with depressive symptoms. METHODS: This cross-sectional study included data from the 2020 Korean Community Health Survey. Depressive symptoms, COVID- 19 protection behaviors, and related factors were investigated in 228,485 people. Chi-square test and logistic regression analysis were used to analyze categorical variables. Statistical analysis was performed using SPSS software (version 27.0). RESULTS: In the study, 3.9% (n=8,970) had depressive symptoms. The prevalence of depressive symptoms was higher in individuals in their 19-39 years , and ≥60s than in those in their 40-59 years (p<0.001). Lower education level and household income were associated with a higher prevalence of depression (p<0.001). Among the various occupations, service workers had the highest prevalence of depressive symptoms (p<0.001). Individuals with depressive symptoms were less likely to adopt protective behaviors against COVID-19 (p<0.001) or exhibit concerns regarding death and economic damage (p<0.001) compared to individuals without depressive symptoms. Individuals with depressive symptoms were more likely to have unhealthy behaviors than those without depressive symptoms (p<0.001). Individuals with depressive symptoms considered that the COVID-19 response by the government and other organizations was inadequate (p<0.001). CONCLUSION: During the COVID-19 pandemic, individuals with depressive symptoms faced greater challenges in adopting protective behaviors. Therefore, it is crucial to develop strategies to protect people with depressive symptoms during another pandemic in the future.