ImportanceSARS-CoV-2 infection is associated with persistent, relapsing, or new symptoms or other health effects occurring after acute infection, termed postacute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Characterizing PASC requires analysis of prospectively and uniformly collected data from diverse uninfected and infected individuals.ObjectiveTo develop a definition of PASC using self-reported symptoms and describe PASC frequencies across cohorts, vaccination status, and number of infections.Design, Setting, and ParticipantsProspective observational cohort study of adults with and without SARS-CoV-2 infection at 85 enrolling sites (hospitals, health centers, community organizations) located in 33 states plus Washington, DC, and Puerto Rico. Participants who were enrolled in the RECOVER adult cohort before April 10, 2023, completed a symptom survey 6 months or more after acute symptom onset or test date. Selection included population-based, volunteer, and convenience sampling.ExposureSARS-CoV-2 infection.Main Outcomes and MeasuresPASC and 44 participant-reported symptoms (with severity thresholds).ResultsA total of 9764 participants (89% SARS-CoV-2 infected; 71% female; 16% Hispanic/Latino; 15% non-Hispanic Black; median age, 47 years [IQR, 35-60]) met selection criteria. Adjusted odds ratios were 1.5 or greater (infected vs uninfected participants) for 37 symptoms. Symptoms contributing to PASC score included postexertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, palpitations, changes in sexual desire or capacity, loss of or change in smell or taste, thirst, chronic cough, chest pain, and abnormal movements. Among 2231 participants first infected on or after December 1, 2021, and enrolled within 30 days of infection, 224 (10% [95% CI, 8.8%-11%]) were PASC positive at 6 months.Conclusions and RelevanceA definition of PASC was developed based on symptoms in a prospective cohort study. As a first step to providing a framework for other investigations, iterative refinement that further incorporates other clinical features is needed to support actionable definitions of PASC.

This work illustrates the reductive coupling of electron-rich aryl halides with tertiary alkyl halides under Ni-catalyzed cross-electrophile coupling conditions, which offers an efficient protocol for the construction of all carbon quaternary stereogenic centers. The mild and easy-to-operate reaction tolerates a wide range of functional groups. The utility of this method is manifested by the preparation of cyclotryptamine derivatives, wherein successful incorporation of 7-indolyl moieties is of particular interest as numerous naturally occurring products are composed of these key scaffolds. DFT calculations have been carried out to investigate the proposed radical chain and double oxidative addition pathways, which provide useful mechanistic insights into the part of the reaction that takes place in solution.

We report the enantioselective synthesis of tetracyclic indolines using cooperative silver(I) and chiral phosphoric acid catalysis. A variety of alkyne-tethered indoles are suitable for this process. Mechanistic studies suggest that the in situ-generated silver(I) chiral phosphate activates both the alkyne and the indole nucleophile in the initial cyclization step through an intermolecular hydrogen bond and the phosphate anion promotes proton transfer. In addition, further modifications of the cyclization products enabled stereochemistry-function studies of a series of bioactive indolines.

DFT computations reveal different reaction mechanisms for the oxidative addition of C(sp)-F and C(sp)-F bonds to the Al(i) complexes: a concerted mechanism for C(sp)-F and a stepwise mechanism for C(sp)-F involving fluoride transfer and the formation and recombination of an ion pair.

We present a detailed DFT mechanistic study on the first Ni-catalyzed direct carbonyl-Heck coupling of aryl triflates and aldehydes to afford ketones.