Enantiospecific cyclization of methyl N-(tert-butoxycarbonyl)-N-(3-chloropropyl)-D-alaninate to 2-methylproline derivative via ‘memory of chirality’ in flow

We report for the very first time a continuous-flow route to perform the intramolecular cyclization of haloalkyl-substituted α-amino esters via memory of chirality (MoC), using lithium bis(trimethylsilyl)amine as a base and methyl N-(tert-butoxycarbonyl)-N-(3-chloropropyl)-D-alaninate as a model reactant. The various reaction parameters, such as temperature, residence time, reactant stoichiometry, or type and concentration of the base were optimized to maximize the yield of the cyclized product and its enantiomeric excess. At the conditions identified, the reaction was eventually scaled up, reaching a productivity of 11 g h−1. Compared to the standard batch protocols available in the literature, the use of a microreactor enables a better control of the exothermicity associated with the addition of the organolithium reagent to the reaction mixture, resulting in operations at more practical temperatures, with high enantiospecificity and full conversion of the reactive amino ester within a few seconds of residence time. [Figure not available: see fulltext.]

Electrophile, Substrate Functionality, and Catalyst Effects in the Synthesis of α-Mono and Di-Substituted Benzylamines via Visible-Light Photoredox Catalysis in Flow

We report herein the facile and one-pot synthesis of α-mono- and di-substituted benzylamines from cheap and readily available α-amino acids, via photocatalytic decarboxylative arylation in flow. This enables to access intermediates and building blocks that are difficult to obtain via other synthetic routes, but are key for the manufacture of pharmaceuticals, agrochemicals, and fine chemicals. The optimal decarboxylative conditions were identified through a high-throughput evaluation of catalysts, organic or inorganic bases, ligands, and reaction parameters (i. e., contact time, temperatures, and photoelectron power). The reaction turned out to be electronically controlled as the yields increased with increasing electron-density on the aryl moiety. The results were correlated with the redox properties of the photocatalysts, deriving catalyst structure-performance relationships which can facilitate the future identification of even better materials. In addition, compared to traditional batch chemistry, the use of a flow protocol led to quicker reactions (30 min instead of 12–72 h) and ensured more predictable reaction scale-ups

A Novel and Efficient Continuous-Flow Route to Prepare Trifluoromethylated N-Fused Heterocycles for Drug Discovery and Pharmaceutical Manufacturing

Continuous-flow processing has become one of the fastest-growing research areas in chemistry in the last 10 years. Herein we disclose an automated and scalable continuous-flow route for the quick introduction of trifluoromethyl groups on a variety of heterocycles, with application in drug discovery and manufacturing. This involves the direct alkylation-cyclization of amines in the presence of trifluoroacetic acid or anhydride, cheap and readily available CF3-containing building blocks. Compared to traditional batch reactions involving an intermediate purification step, the continuous-flow reactions occurred quickly and at mild conditions, with high yield and broad functional-group tolerance. The practical utility of the method was demonstrated by a gram-scale synthesis and by the estimation of modern green metrics

Development of an efficient and sustainable synthesis of 2-(3-methyl-1: H-1,2,4-triazol-1-yl) acetic acid under continuous-flow conditions

A novel, metal-free process for the challenging synthesis of 2-(3-methyl-1H-1,2,4-triazol-1-yl) acetic acid is reported, which features an efficient construction of the triazole ring under flow conditions. This continuous, one-pot method is atom economical, highly selective and environmentally benign, due to the avoidance of chromatography and isolation steps. Compared to the earlier batch routes, higher yields were achieved in a flow reactor. In addition, a highly-energetic intermediate could be controlled and handled in a safe manner. To generalize the established route, several triazoles were prepared under the described conditions, confirming that the methodology could find useful applications for the rapid and sustainable construction of differentially-functionalized 1,2,4-triazoles

Large birds travel farther in homogeneous environments

Aim: Animal movement is an important determinant of individual survival, population dynamics and ecosystem structure and function. Nonetheless, it is still unclear how local movements are related to resource availability and the spatial arrangement of resources. Using resident bird species and migratory bird species outside the migratory period, we examined how the distribution of resources affects the movement patterns of both large terrestrial birds (e.g., raptors, bustards and hornbills) and waterbirds (e.g., cranes, storks, ducks, geese and flamingos). Location: Global. Time period: 2003–2015. Major taxa studied: Birds. Methods: We compiled GPS tracking data for 386 individuals across 36 bird species. We calculated the straight‐line distance between GPS locations of each individual at the 1‐hr and 10‐day time‐scales. For each individual and time‐scale, we calculated the median and 0.95 quantile of displacement. We used linear mixed‐effects models to examine the effect of the spatial arrangement of resources, measured as enhanced vegetation index homogeneity, on avian movements, while accounting for mean resource availability, body mass, diet, flight type, migratory status and taxonomy and spatial autocorrelation. Results: We found a significant effect of resource spatial arrangement at the 1‐hr and 10‐day time‐scales. On average, individual movements were seven times longer in environments with homogeneously distributed resources compared with areas of low resource homogeneity. Contrary to previous work, we found no significant effect of resource availability, diet, flight type, migratory status or body mass on the non‐migratory movements of birds. Main conclusions: We suggest that longer movements in homogeneous environments might reflect the need for different habitat types associated with foraging and reproduction. This highlights the importance of landscape complementarity, where habitat patches within a landscape include a range of different, yet complementary resources. As habitat homogenization increases, it might force birds to travel increasingly longer distances to meet their diverse needs.National Trust for Scotland; Penguin Foundation; The U.S. Department of Energy, Grant/Award Number: DE-EE0005362; Australian Research Council; NASA's Arctic Boreal Vulnerability Experiment (ABoVE), Grant/Award Number: NNX15AV92A; Netherlands Organization for Scientific Research, Grant/Award Number: VIDI 864.10.006; BCC; NSF Award, Grant/Award Number: ABI-1458748; U.K. Department for Energy and Climate Change; ‘Juan de la Cierva ‐ Incorporación’ postdoctoral grant; Irish Research Council, Grant/Award Number: GOIPD/2015/81 ; DECC; Goethe International Postdoctoral Programme, People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007‐2013/ under REA grant agreement no [291776]; German Aerospace Center Award, Grant/Award Number: 50JR1601; Scottish Natural Heritage; Solway Coast AONB Sustainable Development Fund; COWRIE Ltd.; Heritage Lottery Fund; Robert Bosch Stiftung; NSF Division of Biological Infrastructure Award, Grant/Award Number: 1564380; Spanish Ministry of Economy and Competitiveness, Grant/Award Number: IJCI-2014-19190; Energinet.dk; NASA Award, Grant/Award Number: NNX15AV92A; MAVA Foundation; Fundação para a Ciência e Tecnologia, Grant/Award Number: SFRH/BPD/118635/2016; National Key R&D Program of China, Grant/Award Number: 2016YFC0500406; Green Fund of the Greek Ministry of Environmen

Tracking data highlight the importance of human-induced mortality for large migratory birds at a flyway scale

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.publishedVersio

Data from: Large birds travel farther in homogeneous environments

Aim: Animal movement is an important determinant of individual survival, population dynamics, and ecosystem structure and function. Yet it is still unclear how local movements are related to resource availability and the spatial arrangement of resources. Using resident bird species and migratory bird species outside of the migratory period, we examined how the distribution of resources affect the movement patterns of both large terrestrial birds (e.g., raptors, bustards, hornbills) and waterbirds (e.g., cranes, storks, ducks, geese, flamingos). Location: Global Time Period: 2003 - 2015 Major taxa studied: Birds Methods: We compiled GPS tracking data for 386 individuals across 36 bird species. We calculated the straight-line distance between GPS locations of each individual at the 1-hour and 10-day timescales. For each individual and timescale, we calculated the median and 0.95 quantile of displacement. We used linear mixed-effects models to examine the effect of the spatial arrangement of resources, measured as Enhanced Vegetation Index (EVI) homogeneity, on avian movements while accounting for mean resource availability, body mass, diet, flight type, migratory status and taxonomy and spatial autocorrelation. Results: We found a significant effect of resource spatial arrangement at the 1-hour and 10-day timescales. On average, individual movements were seven times longer in environments with homogeneously distributed resources compared with areas of low resource homogeneity. Contrary to previous work, we found no significant effect of resource availability, diet, flight type, migratory status or body mass on the non-migratory movements of birds. Main conclusions: We suggest that longer movements in homogeneous environments may reflect the need for different habitat types associated with foraging and reproduction. This highlights the importance of landscape complementarity, where habitat patches within a landscape include a range of different, yet complimentary resources. As habitat homogenisation increases, it may force birds to travel increasingly longer distances to meet their diverse needs

Bird Movement and EVI Homogeneity Data

Data from Tucker et al. Large birds travel farther in homogeneous environments. Data includes species names, median displacement (km), 0.95 quantile displacement (km), body mass (g), mean EVI value and EVI homogeneity values