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The cascade functionalizations of alkynes have provided many elegant methods for the synthesis of useful scaffolds. Amongst these functionalizations, the ones comprising C−C and C−O bond formation have been utilized extensively due to the abundant presence of oxygenated motifs in various bio‐active natural as well as unnatural products. Transition‐metal catalysis is a mainstay for these tandem functionalizations as they are very efficient. However, their utilization does typically involve stoichiometric additives like other metal salts and/or Lewis acids/Brønsted acids (LA/BA). Thus, approaches that rely solely on using LA/BA, make these vital transformations not only eco‐friendly and atom economical but also cost beneficial are fast emerging as complementary alternatives. The present review addresses the gap in the literature by summarizing recent developments in LA/BA mediated 1,1/1,2‐carboxygenation and carboalkoxylation of alkynes for the synthesis of oxa‐cycles. The reaction mechanisms are particularly emphasized to bring out understanding needed from the point of future developments in this domain. [ABSTRACT FROM AUTHOR]

Aim: To develop an accurate lab score based on in-hospital patients' potent clinical and biological parameters for predicting COVID-19 patient severity during hospital admission. Methods: To conduct this retrospective analysis, a derivation cohort was constructed by including all the available biological and clinical parameters of 355 COVID positive patients (recovered = 285, deceased = 70), collected in November 2020-September 2021. For identifying potent biomarkers and clinical parameters to determine hospital admitted patient severity or mortality, the receiver operating characteristics (ROC) curve and Fischer's test analysis was performed. Relative risk regression was estimated to develop laboratory scores for each clinical and routine biological parameter. Lab score was further validated by ROC curve analysis of the validation cohort which was built with 50 COVID positive hospital patients, admitted during October 2021-January 2022. Results: Sensitivity vs. 1-specificity ROC curve (>0.7 Area Under the Curve, 95% CI) and univariate analysis (p<0.0001) of the derivation cohort identified five routine biomarkers (neutrophil, lymphocytes, neutrophil: lymphocytes, WBC count, ferritin) and three clinical parameters (patient age, pre-existing comorbidities, admitted with pneumonia) for the novel lab score development. Depending on the relative risk (p values and 95% CI) these clinical parameters were scored and attributed to both the derivation cohort (n = 355) and the validation cohort (n = 50). ROC curve analysis estimated the Area Under the Curve (AUC) of the derivation and validation cohort which was 0.914 (0.883–0.945, 95% CI) and 0.873 (0.778–0.969, 95% CI) respectively. Conclusion: The development of proper lab scores, based on patients' clinical parameters and routine biomarkers, would help physicians to predict patient risk at the time of their hospital admission and may improve hospital-admitted COVID-19 patients' survivability. [ABSTRACT FROM AUTHOR]

Gold-catalyzed 5- exo-dig hydroamination on O -homopropargylic hydroxylamine gave expeditious access to methylene isoxazolidine. Excess catalyst loading led to facile 1,3-sulfonyl migration in a cascade fashion to furnish the isoxazoline. Mechanistic studies using react-IR and NMR as well as crossover experiments indicated that 1,3-sulfonyl group migration is an intramolecular concerted process. The ene-hydroxylamine moiety also underwent dipolar cycloaddition reactions with nitrile oxide and nitrones leading to the first examples of spirocyclic bis -isoxazolidine derivatives.