Triphen­yl(tetra­hydro­furan)­aluminium(III)

In the title compound, [Al(C6H5)3(C4H8O)], the Al atom has a distorted tetra­hedral geometry. The C—Al—C angles range from 113.25 (7) to 116.27 (8)°, much larger than the O—Al—C angles, which range from 103.39 (7) to 103.90 (6)°. The tetra­hydro­furan ring adopts an envelope conformation. The crystal packing is stabilized by C—H⋯π inter­actions

An efficient nickel-catalyzed alkenylation of functionalized benzylic halides with alkenylaluminum reagents

Highly efficient and simple coupling reactions of benzylic bromides or chlorides with alkenylaluminum reagents catalyzed by NiCl2(PPh3)(2) are reported. The coupling reactions proceed effectively at room temperature employing low loading of catalyst, 0.5 mol% for benzylic bromides having either electron-donating or -withdrawing substituents on the aromatic ring, affording coupling products in excellent yields of up to 94% in short reaction times. The coupling reactions of benzylic chloride require 5 mol% of the catalyst and a longer reaction time of 2 h

A new chiral ligand: 2,6-bis 4(S)-isopropyl-1-phenyl-4,5-dihydro-1H-imidazol-2-yl pyridine

The title compound, C29H33N5, is a new chiral bis(imidazolyl) pyridine derivative with a skeleton similar to the bis(oxazolyl) pyridine derivatives, which have been extensively used as ligands in various asymmetric catalytic reactions. The most prominent feature of the present compound is the considerable sp(2) character of N atoms of the imidazoline rings. The substituents at the Nsp(2) atoms can provide a means for tuning the electronic and conformational properties of the compound

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic. Funding: Bill & Melinda Gates Foundation

Room Temperature and Highly Enantioselective Additions of Alkyltitanium Reagents to Aldehydes Catalyzed by a Titanium Catalyst of (R)-H-8-BINOL

Three alkyltitanium reagents of RTi(O-i-Pr)(3) (R = Cy (1a), i-Bu (1b), and n-Bu (1c)) were prepared in good yields. The high-resolution mass spectroscopy showed that 1b and 1c in the gas phase are monomeric species. However, the solid state of 1a revealed a dimeric structure. Asymmetric additions of 1a-1c to aldehydes catalyzed by a titanium catalyst of (R)-H-8-BINOL were studied at room temperature. The reactions produced desired secondary alcohols in good yields with good to excellent enantioselectivities of up to 94% ee. Reactivity and enantioselectivity differences, in terms of steric bulkiness of the R nucleophiles, are herein described. The addition reactions of secondary c-hexyl to aldehydes were slower than the reactions of primary i-butyl or n-butyl nucleophiles. For the primary alkyls, lower enantioselectivities were obtained for products from addition reactions of the linear n-butyl as compared with the enantioselectivities of products from the addition reactions of the branched i-butyl group. The same stereochemistry of RTi(O-i-Pr)(3) addition reactions as the addition reactions of organozinc, organoaluminum, Grignard, or organolithium reagents directly supports the argument of that titanium- catalyzed addition reactions of aldehydes involve an addition of an organotitanium nucleophile. Chirality 23:929-939, 2011. (C) 2011 Wiley-Liss, Inc

Synthesis of Allenes via Nickel-Catalyzed Cross-Coupling Reaction of Propargylic Bromides with Grignard Reagents

We describe a convenient method for the synthesis of terminal allenes from cross-coupling of propargylic bromide with Grignard reagent. The reaction of propargylic bromide with 1.2 equivalents of Grignard reagent mediated by Ni(acac)(2) (2 mol%) and Ph3P (4 mol%) in THF may produce terminal allenes in good yields and high regioselectivities at room temperature

Dichlorido(N,N '-dibenzylideneethane-1,2-diamine-kappa N-2,N ') (2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(diphenylmethan-olato)-kappa O-2,O ' titanium(IV)

The title compound, [TiCl2(C31H28O4)(C16H16N2)], is a titanium(IV) complex of the bidentate 2,2-dimethyl-, alpha,alpha,alpha ',alpha '-tetraphenyl-1,3-dioxolane-4,5-dimethanolate (TAD-DOLate) ligand containing also two chloride ions and a bidentate neutral N,N '-dibenzylideneethane-1,2-diamine ligand. The molecular structure has a distorted octahedral geometry around the titanium metal center. The Ti-N bond lengths of 2.246 ( 2) and 2.2476 ( 17) angstrom are long, indicating weak bonding between the titanium( IV) metal center and the imine N atoms. Though the two chloride ligands are trans to each other, they bend away from the Ti-TADDOLate bonds with a Cl-Ti-Cl angle of 163.96 ( 3)degree

Reactions of Ti(O-i-Pr)Cl-3 with 2-aminophenol and the crystal structure of the zwitterionic complex Ti(O-i-Pr)Cl-3(THF)(-OC6H4NH3+) center dot THF

Ti(O-i-Pr)Cl-3 reacts with 1 molar equivalent of 2-aminophenol (HOC6H4NH2) in CH2Cl2 to afford the likely zwitterionic complex [Ti(O-i-Pr) Cl-3(OC6NH3)](2) (1). However, when the reaction is carried out in THF, another zwitterionic complex [Ti(O-i-Pr)-Cl-3(THF) (OC6H4NH3)].(THF) (2) is obtained. With the addition of Ti(O-i-Pr) Cl-3 to a mixture of 2-aminophenol and NEt3 in CH2Cl2, the reaction gives the likely monomeric complex [Ti(O-i-Pr)Cl-3(OC6H4NH2)](-) (HNEt3)(+) (3). The role of the amino group and the effect of the addition of NEt3 and the coordinating THF solvent are discussed. The molecular structure of 2 reveals a species containing the zwitterionic 2-ammonium phenoxide ligand. Two THF molecules are found in the solid state structure in which one THF coordinates to the titanium metal center and the second THF is held tightly via the hydrogen bonding from one ammonium hydrogen. The molecular structure of 2 suggests that the relative bonding abilities of the ligands are in the order of O--i-Pr > -OAr > Cl- > THF. (C) 1998 Elsevier Science S.A. All rights reserved