COVID-19 pandemic effects on health worker's mental health: Systematic review and meta-analysis.

BACKGROUND: Healthcare workers (HCWs) exposed to coronavirus 19 (COVID-19) are at high risk of developing mental health concerns across several domains. The aim of this study is to determine the updated, global frequency of these outcomes. METHODS: A multistep literature search was performed from database inception until March 1, 2021. PRISMA/MOOSE-compliant systematic review and PROSPERO protocol were used to identify studies reporting on depression, anxiety, acute stress, post-traumatic symptoms, insomnia, and burnout in HCWs exposed to COVID-19. A quantitative meta-analysis with random effects was conducted to analyze the proportion rate of the mental health disorders. Sensitivity analyses were performed to investigate the effect of the different continents and scales. Meta-regression analyses were conducted to examine the effect of gender, age, and work position. RESULTS: 239 articles were included (n = 271,319 HCWs, mean age = 36.08 ± 8.33 (66.99% female). 33% HCWs exposed to COVID-19 reported depressive symptoms (95% confidence intervals [CI] = 28-38%), 42% anxiety features (95% CI = 35-48), 40% acute stress (95% CI = 32-47), 32% post-traumatic symptoms (95% CI = 26-37%), 42% insomnia (95% CI = 36-48), 37% burnout (95% CI = 31-42). Sensitivity analyses did not show statistically significant differences. Meta-regressions found a statistically significant lower prevalence of post-traumatic symptoms in Asia. CONCLUSIONS: HCWs exposed to COVID-19 were found to have a significant prevalence of mental health concerns in all domains analyzed. The effects of COVID-19 on HCWs' mental health could be underestimated and the future consequences dismissed.

Exploiting Carbonyl Groups to Control Intermolecular Rhodium-Catalyzed Alkene and Alkyne Hydroacylation.

Readily available ß-carbonyl-substituted aldehydes are shown to be exceptional substrates for Rh-catalyzed intermolecular alkene and alkyne hydroacylation reactions. By using cationic rhodium catalysts incorporating bisphosphine ligands, efficient and selective reactions are achieved for ß-amido, ß-ester, and ß-keto aldehyde substrates, providing a range of synthetically useful 1,3-dicarbonyl products in excellent yields. A correspondingly broad selection of alkenes and alkynes can be employed. For alkyne substrates, the use of a catalyst incorporating the Ampaphos ligand triggers a regioselectivity switch, allowing both linear and branched isomers to be prepared with high selectivity in an efficient manner. Structural data, confirming aldehyde chelation, and a proposed mechanism are provided.

Sequential catalysis: exploiting a single rhodium(i) catalyst to promote an alkyne hydroacylation-aryl boronic acid conjugate addition sequence.

We demonstrate that a single Rh(i) complex can promote two mechanistically distinct C-C bond-forming reactions - alkyne hydroacylation and aryl boronic acid conjugate addition - to deliver substituted ketone products from the controlled assembly of three readily available fragments. This is a rare example of a Rh(i)/Rh(iii) cycle and a redox neutral Rh(i) cycle being promoted by a single catalyst. The process is broad in scope, allowing significant variation of all three reaction components. Incorporation of an enantiomerically pure bis-phosphine ligand renders the process enantioselective. Superior levels of enantioselectivity (up to >99% ee) can be achieved from using a two catalyst system, whereby two Rh(i) complexes, one incorporating an achiral bis-phosphine ligand and the second a chiral diene ligand, are introduced at the start of the reaction sequence.

Synthesis of Pyrrolo[2,3-d]pyrimidines by Copper-Mediated Carbomagnesiations of N-Sulfonyl Ynamides and Application to the Preparation of Rigidin†A and a 7-Azaserotonin Derivative.

The treatment of readily available N-alkynyl-5-iodo-6-sulfamido-pyrimidines with iPrMgCl⋅LiCl followed by a transmetalation with CuCN⋅2 LiCl produces, after intramolecular carbocupration, metalated pyrrolo[2,3-d]pyrimidines. Quenching of these pyrimidines with allylic halides or acid chlorides results in polyfunctional pyrrolo[2,3-d]pyrimidines. Further reaction with ICl and a Negishi cross-coupling, using PEPPSI-iPr as the catalyst, furnishes fully substituted N-heterocycles. A formal synthesis of the marine alkaloid rigidin A has been achieved as well as the preparation of a derivative of 7-azaserotonine, related to the natural hormone serotonin.

Well-Defined and Robust Rhodium Catalysts for the Hydroacylation of Terminal and Internal Alkenes.

A Rh-catalyst system based on the asymmetric ligand (t)Bu2PCH2P(o-C6H4OMe)2 is reported that allows for the hydroacylation of challenging internal alkenes with ß-substituted aldehydes. Mechanistic studies point to the stabilizing role of both excess alkene and the OMe-group.

Enantioselective Synthesis of Tertiary Propargylic Alcohols under N-Heterocyclic Carbene Catalysis.

A straightforward procedure to carry out the enantioselective benzoin reaction between aldehydes and ynones by employing a chiral N-heterocyclic carbene (NHC) as catalyst was developed. Under the optimized reaction conditions, these ynones undergo a clean and selective 1,2-addition with the catalytically generated Breslow intermediate, not observing any byproduct arising from competitive Stetter-type reactivity. This procedure allows the preparation of tertiary alkynyl carbinols as highly enantioenriched materials, which have the remarkable potential to be used as chiral building blocks in organic synthesis.

New in situ trapping metalations of functionalized arenes and heteroarenes with TMPLi in the presence of ZnCl2 and other metal salts.

The addition of TMPLi to a mixture of an aromatic or heteroaromatic substrate with a metal salt such as MgCl2, ZnCl2, or CuCN at -78 °C first leads to lithiation of the arene followed by transmetalation with the metal salt to afford functionalized organometallic compounds of Mg, Zn, or Cu. This in situ trapping method allows an expedited metalation (-78 °C, 5 min) of a range of sensitive pyridines (bearing a nitro, ester, or cyano group) and allows the preparation of kinetic regioisomers of functionalized aromatic compounds or heterocycles not otherwise available by standard metalating agents, such as TMPMgCl⋅LiCl or TMPZnCl⋅LiCl.

Ethyl glyoxylate N-tosylhydrazone as sulfonyl-transfer reagent in base-catalyzed sulfa-Michael reactions.

Ethyl glyoxylate N-tosylhydrazone has been identified as an excellent sulfonyl anion surrogate in the DBU-catalyzed conjugate addition reaction with enones and enals for the synthesis of functionalized sulfones. The reaction proceeds under base-catalyzed conditions and provides a direct access to γ-keto- and γ-hydroxy sulfones in a simple and reliable way through a sulfa-Michael reaction that proceeds with high yield and chemoselectivity.

Enantioselective conjugate addition of donor-acceptor hydrazones to α,ß-unsaturated aldehydes through formal diaza-ene reaction: access to 1,4-dicarbonyl compounds.

Donor-acceptor monosubstituted hydrazones participate as suitable reagents able to undergo an enantioselective formal diaza-ene reaction with α,ß-unsaturated aldehydes under chiral secondary amine catalysis. This constitutes a new approach for the enantioselective conjugate addition of hydrazones to enals under metal-free conditions and leads to the formation of γ-hydrazono carboxylic acids after oxidation/[1,3]-H shift. The methodology is also useful for the synthesis of enantioenriched ß-substituted α-keto-1,5-diesters by using the hydrazone moiety as a masked carbonyl group.

Organocatalytic enantioselective synthesis of 2,3-dihydropyridazines.

We have developed an efficient procedure for the easy and straightforward preparation of functionalized dihydropyridazines as highly enantiopure materials by reaction of pyruvaldehyde 2-tosyl hydrazone with a variety of α,ß-unsaturated aldehydes using a chiral secondary amine as catalyst. The overall process consists of a cascade reaction involving an initial aza-Michael reaction, in which the stereocentre is installed, followed by an intramolecular aldol reaction/dehydration step.