Browsing by Subject "EFFICIENCY"

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  • Reilas, Tiina; Katila, Terttu; Kosola, Mikko; Virtala, Anna-Maija (2020)
    In Finland, the seasonal foaling rates of trotters began declining at the beginning of the 2000s. This retrospective study aimed to elaborate factors behind the declining foaling rates in Finnhorses using multivariable logit models. The mating records from years 1998 to 2000 (period 1, n = 5967) and 2002 to 2004 (period 2, n = 5373) originated from the Finnish trotting and breeding association. The over-all foaling rate was 66.6% during period 1 and 62.4% during period 2 (p < 0.0001). Foaling rate for on-site artificial insemination decreased from 70.2% to 64.8% (p = 0.003). The proportion of the most fertile mare groups, 2–9-year-olds and foaled mares, decreased by 8.2 and 7.1 percentage points, respectively. Differences in foaling rates between young and middle-aged mares, and maiden and foaled mares changed from non-significant to significant (p<0.0001) due to the foaling rate decline in middle-aged (p = 0.001) and maiden mares (p = 0.01). The decline in foaling rate was also significant for barren and rested mares (p < 0.05), natural mating (p = 0.01), and book size >68 (p < 0.0001). It was concluded that multiple factors were responsible for the foaling rate decline.
  • Chawade, Aakash; Armoniene, Rita; Berg, Gunilla; Brazauskas, Gintaras; Frostgard, Gunilla; Geleta, Mulatu; Gorash, Andrii; Henriksson, Tina; Himanen, Kristiina; Ingver, Anne; Johansson, Eva; Jorgensen, Lise Nistrup; Koppel, Mati; Koppel, Reine; Makela, Pirjo; Ortiz, Rodomiro; Podyma, Wieslaw; Roitsch, Thomas; Ronis, Antanas; Svensson, Jan T.; Vallenback, Pernilla; Weih, Martin (2018)
    The Baltic Sea is one of the largest brackish water bodies in the world. Eutrophication is a major concern in the Baltic Sea due to the leakage of nutrients to the sea with agriculture being the primary source. Wheat (Triticum aestivum L.) is the most widely grown crop in the countries surrounding the Baltic Sea and thus promoting sustainable agriculture practices for wheat cultivation will have a major impact on reducing pollution in the Baltic Sea. This approach requires identifying and addressing key challenges for sustainable wheat production in the region. Implementing new technologies for climate-friendly breeding and digital farming across all surrounding countries should promote sustainable intensification of agriculture in the region. In this review, we highlight major challenges for wheat cultivation in the Baltic Sea region and discuss various solutions integrating transnational collaboration for pre-breeding and technology sharing to accelerate development of low input wheat cultivars with improved host plant resistance to pathogen and enhanced adaptability to the changing climate.
  • Garofalo, M.; Saari, H.; Somersalo, P.; Crescenti, D.; Kuryk, L.; Aksela, L.; Capasso, C.; Madetoja, M.; Koskinen, K.; Oksanen, T.; Mäkitie, A.; Jalasvuori, M.; Cerullo, V.; Ciana, P.; Yliperttula, M. (2018)
    Standard of care for cancer is commonly a combination of surgery with radiotherapy or chemoradiotherapy. However, in some advanced cancer patients this approach might still remaininefficient and may cause many side effects, including severe complications and even death. Oncolytic viruses exhibit different anti-cancer mechanisms compared with conventional therapies, allowing the possibility for improved effect in cancer therapy. Chemotherapeutics combined with oncolytic viruses exhibit stronger cytotoxic responses and oncolysis. Here, we have investigated the systemic delivery of the oncolytic adenovirus and paclitaxel encapsulated in extracellular vesicles (EV) formulation that, in vitro, significantly increased the transduction ratio and the infectious titer when compared with the virus and paclitaxel alone. We demonstrated that the obtained EV formulation reduced the in vivo tumor growth in animal xenograft model of human lung cancer. Indeed, we found that combined treatment of oncolytic adenovirus and paclitaxel encapsulated in EV has enhanced anticancer effects both in vitro and in vivo in lung cancer models. Transcriptomic comparison carried out on the explanted xenografts from the different treatment groups revealed that only 5.3% of the differentially expressed genes were overlapping indicating that a de novo genetic program is triggered by the presence of the encapsulated paclitaxel: this novel genetic program might be responsible of the observed enhanced antitumor effect. Our work provides a promising approach combining anticancer drugs and viral therapies by intravenous EV delivery as a strategy for the lung cancer treatment.
  • Mantysaari, P.; Mantysaari, E. A.; Kokkonen, T.; Mehtio, T.; Kajava, S.; Grelet, C.; Lidauer, P.; Lidauer, M. H. (2019)
    The inclusion of feed intake and efficiency traits in dairy cow breeding goals can lead to increased risk of metabolic stress. An easy and inexpensive way to monitor postpartum energy status (ES) of cows is therefore needed. Cows' ES can be estimated by calculating the energy balance from energy intake and output and predicted by indicator traits such as change in body weight (Delta BW), change in body condition score (Delta BCS), milk fat:protein ratio (FPR), or milk fatty acid (FA) composition. In this study, we used blood plasma nonesterified fatty acids (NEFA) concentration as a biomarker for ES. We determined associations between NEFA concentration and ES indicators and evaluated the usefulness of body and milk traits alone, or together, in predicting ES of the cow. Data were collected from 2 research herds during 2013 to 2016 and included 137 Nordic Red dairy cows, all of which had a first lactation and 59 of which also had a second lactation. The data included daily body weight, milk yield, and feed intake and monthly BCS. Plasma samples for NEFA were collected twice in lactation wk 2 and 3 and once in wk 20. Milk samples for analysis of fat, protein, lactose, and FA concentrations were taken on the blood sampling days. Plasma NEFA concentration was higher in lactation wk 2 and 3 than in wk 20 (0.56 +/- 0.30, 0.43 +/- 0.22, and 0.13 +/- 0.06 mmol/L, respectively; all means +/- standard deviation). Among individual indicators, C18:1 cis-9 and the sum of C18:1 in milk had the highest correlations (r = 0.73) with NEFA. Seven multiple linear regression models for NEFA prediction were developed using stepwise selection. Of the models that included milk traits (other than milk FA) as well as body traits, the best fit was achieved by a model with milk yield, FPR, Delta BW, Delta BCS, FPR x Delta BW, and days in milk. The model resulted in a cross-validation coefficient of determination (R(2)cv) of 0.51 and a root mean squared error (RMSE) of 0.196 mmol/L. When only milk FA concentrations were considered in the model, NEFA prediction was more accurate using measurements from evening milk than from morning milk (R(2)cv = 0.61 vs. 0.53). The best model with milk traits contained FPR, C10:0, C14:0, C18:1 cis-9, C18:1 cis-9 x C14:0, and days in milk (R(2)cv = 0.62; RMSE = 0.177 mmol/L). The most advanced model using both milk and body traits gave a slightly better fit than the model with only milk traits (R(2)cv = 0.63; RMSE = 0.176 mmol/L). Our findings indicate that ES of cows in early lactation can be monitored with moderately high accuracy by routine milk measurements.
  • Vainio, Annukka; Pulkka, Anna; Paloniemi, Riikka; Varho, Vilja; Tapio, Petri (2020)
    This study explored individuals' engagement in the sustainable energy transition in Finland. Using the attitude-behaviour-context model (Guagnano et al., 1995) and Stern's (2000) typology of environmentally significant behaviours, this study tested the assumption that individuals' engagement in transition is a combination of socio-psychological and contextual (socio-economic) variables and that the active engagement requires individuals to have a future orientation, systemic and self-efficacy, subjective knowledge and a pro-environmental attitude. The survey (N = 1012), representative of the 17-75-yearold Finnish population, was analysed with exploratory factor analysis and linear regression. The socio-psychological variables explained a larger portion of variance than the socio-economic variables in all three types of sustainable energy behaviours. The consideration of future consequences, self-efficacy and knowledge were positively associated with all three types of sustainable energy behaviours. Systemic efficacy was positively associated with and the consideration of immediate consequences was negatively associated with private-sphere environmentalism. The results suggest that individuals' consideration of the immediate and distant future should be included in the socio-psychological models of sustainable behaviours. The results also suggest that policymakers need to focus on strengthening citizens' efficacy beliefs, future orientation and knowledge. (C) 2019 The Authors. Published by Elsevier Ltd.
  • Benatto, L.; Marchiori, C. F. N.; Talka, T.; Aramini, M.; Yamamoto, N. A. D.; Huotari, S.; Roman, L. S.; Koehler, M. (2020)
    The difference in aggregation size of the C-60 and C-70 fullerenes affect the photovoltaic performance of devices assembled in the so-called bilayer architecture with poly [2,7-(9,9- dioctyl- dibenzosilole)- alt-4,7- bis(thiophen-2-yl)benzo- 2,1,3- thiadiazole] (PSiF-DBT) as the electron donor material. Despite the better performance of the C-70 devices, which is related to the high absorption coefficient in the visible range and the superior charge transport properties, the short-circuit current variation upon annealing treatment at 100 degrees C is approximately twice bigger when the C-60 is the acceptor. We attribute this effect to the tendency of C-60 in form smaller aggregate domains relatively to the C-70. The increased roughness on the polymeric surface after annealing results in an enhanced donor/acceptor contact area and assists the fullerene diffusion deeper inside the polymeric layer. This effect leads to a better mixing between donor and acceptor species and create a interpenetrating layer close to the so-called bulk heterojunction. Since C-60 forms smaller aggregates, this mechanism is more pronounced for this molecule. Therefore, a significant variation in the performance of the C-60 devices is observed after this kind of treatment. Density Functional Theory calculations of the potential energy of interaction between two fullerene molecules and X-Ray measurements gives evidences to support this idea. In addition, combining spectrally resolved external quantum efficiency measurements with optical modeling our results also indicate the occurrence of the bilayer interfacial mixing for PSiF-DBT/C-60.
  • Haapaniemi, Emma; Botla, Sandeep; Persson, Jenna; Schmierer, Bernhard; Taipale, Jussi (2018)
    Here, we report that genome editing by CRISPR-Cas9 induces a p53-mediated DNA damage response and cell cycle arrest in immortalized human retinal pigment epithelial cells, leading to a selection against cells with a functional p53 pathway. Inhibition of p53 prevents the damage response and increases the rate of homologous recombination from a donor template. These results suggest that p53 inhibition may improve the efficiency of genome editing of untransformed cells and that p53 function should be monitored when developing cell-based therapies utilizing CRISPR-Cas9.
  • Mõttus, Matti; Aragão, Luiz; Bäck, Jaana; Clemente, Rocío Hernandez; Maeda, Eduardo Eiji; Markiet, Vincent Robert Leon; Nichol, Caroline; Oliveira, Raimundo Cosme; Restrepo-Coupe, Natalia (2019)
    The spectral properties of plant leaves relate to the state of their photosynthetic apparatus and the surrounding environment. An example is the well known photosynthetic downregulation, active on the time scale from minutes to hours, caused by reversible changes in the xanthophyll cycle pigments. These changes affect leaf spectral absorption and are frequently quantified using the photochemical reflectance index (PRI). This index can be used to remotely monitor the photosynthetic status of vegetation, and allows for a global satellite-based measurement of photosynthesis. Such earth observation satellites in near-polar orbits usually cover the same geographical location at the same local solar time at regular intervals. To facilitate the interpretation of these instantaneous remote PRI measurements and upscale them temporally, we measured the daily course of leaf PRI in two evergreen biomes—a European boreal forest and an Amazon rainforest. The daily course of PRI was different for the two locations: At the Amazonian forest, the PRI of Manilkara elata leaves was correlated with the average photosynthetic photon flux density (PPFD) ( R2=0.59 ) of the 40 minutes preceding the leaf measurement. In the boreal location, the variations in Pinus sylvestris needle PRI were only weakly ( R2=0.27) correlated with mean PPFD of the preceding two hours; for Betula pendula, the correlation was insignificant regardless of the averaging period. The measured daily PRI curves were specific to species and/or environmental conditions. Hence, for a proper interpretation of satellite-measured instantaneous photosynthesis, the scaling of PRI measurements should be supported with information on its correlation with PPFD.
  • Ebrahimi, Nashmin; Hartikainen, Helina; Simojoki, Asko; Hajiboland, Roghieh; Seppanen, Mervi (2015)
    The uptake by and subsequent translocation of selenium (Se) within the plant is dependent on its chemical form and soil properties that dictate this trace element's bioavailability. Plant species differ in their tendency to accumulate Se. Se taken-up by plants is returned to soil in plant residues, but the bioavailability of organic Se in those residues is poorly known. We investigated the impact of inorganic (Na2SeO4), organic (Se-enriched stem and leaf residues) Se applications and also soil microbial respiration on the growth and Se concentrations of various plant organs of oilseed rape (Brassica napus L.) during its development from the rosette to the seed filling stage. Both inorganic and organic Se slightly improved plant growth and enhanced plant development. Inorganic Se was more bioavailable than the organic forms and resulted in 3-fold to 6-fold higher Se concentrations in the siliques. Inorganic Se in autoclaved soil tended to elevate the Se concentration in all plant parts and at all growth stages. The organic Se raised Se concentrations in plants much less effectively than the inorganic selenate. Therefore, the use of inorganic Se is still recommended for biofortification.
  • Friberg, Kalervo (2020)
    This study detected and analyzed changes that took place in students' attitudes toward their future education and occupation after completion of the 3-year orientation to work-life through Grades 7 to 9 in different regions in Finland. The changes in the correlations of attitudes were seen as both precursors and consequences of the students' engagement in the work-life orientation (WLO) program. The changes were postulated not to correlate with the respondents' region and parents' education. The empirically measured changes in students' attitudes served as indicators of the efficacy of WLO. Efficacy referred to the power of WLO to produce effects in the form of changes in attitudes toward educational and occupational choices. Consequently, tentative hypotheses were formed to be tested through empirical observations (measurement points) of WLO. WLO was expected to positively affect student motivation and to guide idiographic decision-making concerning personal goals. Using an alpha level of .05, an independent samples test was conducted to evaluate whether independence, flexibility, and self-direction differed significantly in the measurement groups. For the WLO effect sizes (ES) estimation and for the comparison of the groups, Cohen's ds were calculated. WLO had a small to medium effect on independence and flexibility, and a near zero effect on self-direction. No notable regional differences in the variance of the students' attitudes were detected although the social environments differed considerably with regard to industrial structure. The statistically significant proportional differences between the parents' educational levels did not correlate with the efficacy of WLO.
  • Mendizabal, Fernando; Mera-Adasme, Raul; Xu, Wen-Hua; Sundholm, Dage (2017)
    Dye-sensitized solar-cell (DSSC) systems have been investigated by calculating light-absorption and electron-injection processes of the LD13 ([5,15-bis(2,6-(1,1-dimethylethyl)-phenyl)-10-4-dimethylaminophenylethynyl-20-4-carboxy phenylethynyl porphyrinato]zinc-(II)) and YD2-o-C8 ([5,15bis( 2,6-dioctoxyphenyl)-10-(bis(4-hexylphenyl)amino-20-4-carboxyphenylethynyl)porphyrinato]zinc-(II)) dyes adsorbed on a TiO2 cluster simulating the semiconductor. The binding energy of the dyes with the TiO2 clusters has been calculated at the density functional theory (DFT) level using the B3LYP and CAM-B3LYP functionals. The electronic excitation energies have been calculated at the time-dependent DFT (TDDFT) level for the dyes in the gas and solvent phase employing the B3LYP, CAM-B3LYP and BHLYP functionals. The calculated excitation energies have been compared to values obtained at the algebraic diagrammatic construction through second order (ADC(2)) level of theory. The TDDFT calculations with the B3LYP in tetrahydrofuran solvent with the dye and dye-TiO2 models yield excitation energies that agree well with the transitions in the experimental absorption spectra. Changes in the free energy for electron injection support the better performance of the dyes on the TiO2 clusters.
  • Talon, Emma; Lampi, Anna-Maija; Vargas, Maria; Chiralt, Amparo; Jouppila, Kirsi; Gonzalez-Martinez, Chelo (2019)
    The encapsulation of eugenol (E) by spray-drying using whey protein (WP) or soy lecithin (LE) and maltodextrin in combination with oleic acid (OA) and chitosan (CH) was analysed in order to obtain antioxidant and antimicrobial powders for food applications. Formulations with only WP or LE showed higher encapsulation efficiencies (EE) (95-98%) and antibacterial effect against E. coli and L. innocua due to their greater E load. Incorporation of OA or CH promoted lower EE, which negatively affected the antimicrobial and antioxidant activities of the powders. Furthermore, the addition of CH implied less thermal protection against the E losses. The eugenol release was not notably affected by pH or polarity of the food simulant, but the release rate significantly decreased when incorporating OA and CH. The E-LE formulations better retained the eugenol than E-WP powders when heated above 200 degrees C, this being relevant for the powder inclusion in thermally treated products.
  • Koskelo, J.; Hashemi, J.; Huotari, S.; Hakala, M. (2016)
    We present a comprehensive study of the electronic, magnetic, and optical properties of CuGa1-xFexS2, as a promising candidate for intermediate-band (IB) solar cells. We use hybrid exchange-correlation functional within the density functional theory framework, and show that Fe doping induces unoccupied states 1.6-1.9 eV above the valence band. The IBs significantly enhance the optical absorption in lower energy part of the spectrum. We find that at moderate n-type co-doping concentration, the added charge occupies part of the IB in the gap, but large concentrations lower the energy of the occupied IB toward the valence band. Moreover, we show that Fe impurities tend to cluster within the compound and they choose antiferromagnetic ordering. The findings can have a significant effect in understanding this material and help to synthesize more efficient IB solar cells.
  • Johansson, Karin S. L.; El-Soda, Mohamed; Pagel, Ellen; Meyer, Rhonda C.; Toldsepp, Kadri; Nilsson, Anders K.; Brosche, Mikael; Kollist, Hannes; Uddling, Johan; Andersson, Mats X. (2020)
    Background and Aims The stomatal conductance (g(s)) of most plant species decreases in response to elevated atmospheric CO2 concentration. This response could have a significant impact on plant water use in a future climate. However, the regulation of the CO2 induced stomatal closure response is not fully understood. Moreover, the potential genetic links between short-term (within minutes to hours) and long-term (within weeks to months) responses of g(s) to increased atmospheric CO2 have not been explored. Methods We used Arabidopsis thaliana recombinant inbred lines originating from accessions Col-0 (strong CO2 response) and C24 (weak CO2 response) to study short- and long-term controls of g(s) Quantitative trait locus (QTL) mapping was used to identify loci controlling short- and long-term g(s) responses to elevated CO2 as well as other stomata-related traits. Key Results Short- and long-term stomatal responses to elevated CO2 were significantly correlated. Both short-and long-term responses were associated with a QTL, at the end of chromosome 2. The location of this QTL was confirmed using near-isogonic lines and it was fine-mapped to a 410-kb region. The QTL did not correspond to any known gene involved in stomatal closure and had no effect on the responsiveness to abscisic acid. Additionally, we identified numerous other loci associated with stomatal regulation. Conclusions We identified and confirmed the effect of a strong QTL corresponding to a yet unknown regulator of stomatal closure in response to elevated CO2 concentration. The correlation between short- and long-term stomatal CO2 responses and the genetic link between these traits highlight the importance of understanding guard cell CO2 signalling to predict and manipulate plant water use in a world with increasing atmospheric CO2 concentration. This study demonstrates the power of using natural variation to unravel the genetic regulation of complex traits.
  • Cubbage, Frederick; Kanieski, Bruno; Rubilar, Rafael; Bussoni, Adriana; Morales Olmos, Virginia; Balmelli, Gustavo; Mac Donagh, Patricio; Lord, Roger; Hernandez, Carmelo; Zhang, Pu; Huang, Jin; Korhonen, Jaana; Yao, Richard; Hall, Peter; Del La Torre, Rafael; Diaz-Balteiro, Luis; Carrero, Omar; Monges, Elizabeth; Ha Tran Thi Thu,; Frey, Gregory; Howard, Mike; Chavet, Michael; Mochan, Shaun; Hoeflich, Vitor Afonso; Chudy, Rafal; Maass, David; Chizmar, Stephanie; Abt, Robert (2020)
    We estimated timber investment returns for 22 countries and 54 species/management regimes in 2017, for a range of global timber plantation species and countries at the stand level, using capital budgeting criteria, without land costs, at a real discount rate of 8%. Returns were estimated for the principal plantation countries in the Americas-Brazil, Argentina, Uruguay, Chile, Colombia, Venezuela, Paraguay, Mexico, and the United States-as well as New Zealand, Australia, South Africa, China, Vietnam, Laos, Spain, Finland, Poland, Scotland, and France. South American plantation growth rates and their concomitant returns were generally greater, at more than 12% Internal Rates of Return (IRRs), as were those in China, Vietnam, and Laos. These IRRs were followed by those for plantations in southern hemisphere countries of Australia and New Zealand and in Mexico, with IRRs around 8%. Temperate forest plantations in the U.S. and Europe returned less, from 4% to 8%, but those countries have less financial risk, better timber markets, and more infrastructure. Returns to most planted species in all countries except Asia have decreased from 2005 to 2017. If land costs were included in calculating the overall timberland investment returns, the IRRs would decrease from 3 percentage points less for loblolly pine in the U.S. South to 8 percentage points less for eucalypts in Brazil.
  • Busch, Jasmin M.; Zink, Daniel M.; Di Martino-Fumo, Patrick; Rehak, Florian R.; Boden, Pit; Steiger, Sophie; Fuhr, Olaf; Nieger, Martin; Klopper, Wim; Gerhards, Markus; Bräse, Stefan (2019)
    Luminescent Cu(i) AlkylPyrPhos complexes with a butterfly-shaped Cu2I2 core and halogen containing ancillary ligands, with a special focus on fluorine, have been investigated in this study. These complexes show extremely high solubilities and a remarkable (photo)chemical stability in a series of solvents. A tunable emission resulting from thermally activated delayed fluorescence with high quantum yields was determined by luminescence and lifetime investigations in solvents and solids. Structures of the electronic ground states were analyzed by single crystal X-ray analysis. The structure of the lowest excited triplet state was determined by transient FTIR spectroscopy, in combination with quantum chemical calculations. With the obtained range of compounds we address the key requirement for the production of organic light emitting diodes based on solution processing.
  • Ollila, Laura; Heliö, Tiina; Sovijärvi, Anssi; Jalanko, Mikko; Kaartinen, Maija; Kuusisto, Johanna; Kärkkäinen, Satu; Jurkko, Raija; Reissell, Eeva; Palojoki, Eeva; Piirilä, Päivi (2017)
    BackgroundLMNA mutations are an important cause of cardiomyopathy often leading to cardiac arrhythmias, heart failure and even heart transplantation. An increasing number of asymptomatic mutation carriers are identified, as family members of the index patients are screened. Our aim was to study the disease progression in asymptomatic LMNA mutation carriers and in patients with symptomatic cardiolaminopathy by repeated spiroergometric testing in a prospective clinical follow-up study. Methods and ResultsWe studied 26 LMNA mutation carriers once a year during 5years up to 6 times by spiroergometry, clinical assessment, laboratory tests and echocardiography. The 23 control subjects underwent clinical assessment and spiroergometry once. Twelve of the mutation carriers were asymptomatic, and 14 had some clinical manifestations of the mutation ranging from clinically relevant rhythm disturbances to DCM and heart failure. Compared to controls, the symptomatic carriers showed a higher slope of the ventilatory equivalent for CO2 (VE/VCO2 slope) and a lower fraction of end-tidal CO2 (FetCO(2)). The asymptomatic mutation carriers also showed an increased ventilatory response to exercise during the follow-up as indicated by increased VE/VCO2 slope and decreased FetCO(2). ConclusionsThe study suggests that an increased ventilatory response during exercise might reveal a preclinical manifestation of DCM in LMNA mutation carriers.
  • Hossein Motlagh, Naser; Mohammadrezaei, Mahsa; Hunt, Julian; Zakeri, Behnam (2020)
    Integration of renewable energy and optimization of energy use are key enablers of sustainable energy transitions and mitigating climate change. Modern technologies such the Internet of Things (IoT) offer a wide number of applications in the energy sector, i.e, in energy supply, transmission and distribution, and demand. IoT can be employed for improving energy efficiency, increasing the share of renewable energy, and reducing environmental impacts of the energy use. This paper reviews the existing literature on the application of IoT in in energy systems, in general, and in the context of smart grids particularly. Furthermore, we discuss enabling technologies of IoT, including cloud computing and different platforms for data analysis. Furthermore, we review challenges of deploying IoT in the energy sector, including privacy and security, with some solutions to these challenges such as blockchain technology. This survey provides energy policy-makers, energy economists, and managers with an overview of the role of IoT in optimization of energy systems.
  • Watile, Rahul A.; Bunrit, Anon; Margalef, Jessica; Akkarasamiyo, Sunisa; Ayub, Rabia; Lagerspets, Emi; Biswas, Srijit; Repo, Timo; Samec, Joseph S. M. (2019)
    Optically pure alcohols are abundant in nature and attractive as feedstock for organic synthesis but challenging for further transformation using atom efficient and sustainable methodologies, particularly when there is a desire to conserve the chirality. Usually, substitution of the OH group of stereogenic alcohols with conservation of chirality requires derivatization as part of a complex, stoichiometric procedure. We herein demonstrate that a simple, inexpensive, and environmentally benign iron(III) catalyst promotes the direct intramolecular substitution of enantiomerically enriched secondary and tertiary alcohols with O-, N-, and S-centered nucleophiles to generate valuable 5-membered, 6-membered and aryl-fused 6-membered heterocyclic compounds with chirality transfer and water as the only byproduct. The power of the methodology is demonstrated in the total synthesis of (+)-lentiginosine from D-glucose where iron-catalysis is used in a key step. Adoption of this methodology will contribute towards the transition to sustainable and bio-based processes in the pharmaceutical and agrochemical industries.