Intermolecular oxidative dehydrogenative 3,3 '-coupling of benzo[b]furans and benzo[b]thiophenes promoted by DDQ/H+ : total synthesis of shandougenine B

With an excess of a strong acid, 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ) is shown to promote metal-free intermolecular oxidative dehydrogenative (ODH) 3,3'-coupling of 2-aryl-benzo[b]furans and 2-aryl-benzo[b]thiophenes up to 92% yield as demonstrated with 9 substrates. Based on the analysis of oxidation potentials and molecular orbitals combined with EPR, NMR and UV-Vis observations, the studied reaction is initiated by a DDQ-substrate charge transfer complex and presumably proceeds via oxidation of the substrate into an electrophilic radical cation that further reacts with another molecule of a neutral substrate. The coupling reactivity can easily be predicted from the oxidation potential of the substrate and the morphology of its frontier molecular orbitals. The intermolecular ODH coupling reaction allowed a concise total synthesis of the natural product shandougenine B.Peer reviewe

Modification of national OSCE due to COVID-19-Implementation and students' feedback

Aim The aims were to describe the development of a modified national online OSCE during COVID-19 and assess related student feedback.Material and methods The modified online OSCE comprising of eight question entities was organised simultaneously in all four dental institutes of Finland using the Moodle virtual learning environment. All fourth-year students (n = 179) attended the examination online at home. Student feedback was collected via an anonymous questionnaire with multiple-choice questions and open-ended questions concerning attitudes towards the modified online OSCE, as well as content and usability of the question entities in the examination. Means and standard deviations were calculated for multiple-choice questions. Content analysis was used for open-ended questions.Results Of 179 students, 119 (66%) consented to the study. Students experienced they had received adequate information (mean 3.8; SD 1.2), had a positive attitude before the examination (4.0; 1.0) and found the practice test useful (3.7; 1.1) (range 1-5). Technical implementation (2.7; 0.7) and the difficulty of the questions (2.9; 0.6) (range 1-4) were found to be good. The teaching students received during their studies was sufficient (3.2; 0.5) (range 1-4). Content (mean 3.2; 0.4) and usability (2.9; 0.4) of the question entities were good (range 1-4). The themes arising from open-ended questions were importance and practicality of the topic (in questions) in relation to the work of a dentist and gratitude for the rapid conversion of the OSCE into an online examination despite COVID-19. The themes arising from negative experiences included difficulties in completing the examination within the time allocated, and dissatisfaction with the model answers provided after the examination.Conclusion The positive student feedback towards the modified online OSCE encourages including an online examination to complement the traditional OSCE

Mono- and bis-imidazolidinium ethynyl cations and the reduction of the latter to give an extended bis-1,4-([3]cumulene)-p-carbo-quinoid system

Sherpa Romeo yellow journal. This is the peer reviewed version. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsAn extended π-system containing two [3]cumulene fragments separated by a p-carbo-quinoid and stabilized by two capping N-heterocyclic carbenes (NHCs) has been prepared. Mono- and bis-imidazolidinium ethynyl cations have also been synthesized from the reaction of an NHC with phenylethynyl bromide or 1,4bis(bromoethynyl)benzene. Cyclic voltammetry coupled with synthetic and structural studies showed that the dication is readily reduced to a neutral, singlet bis-1,4-([3]cumulene)-p-carbo-quinoid due to the πaccepting properties of the capping NHCsYe

Opportunities and Challenges in Using Learning Analytics in Learning Design

Educational institutions are designing, creating and evaluating courses to optimize learning outcomes for highly diverse student populations. Yet, most of the delivery is still monitored retrospectively with summative evaluation forms. Therefore, improvements to the course design are only implemented at the very end of a course, thus missing to benefit the current cohort. Teachers find it difficult to interpret and plan interventions just-in-time. In this context, Learning Analytics (LA) data streams gathered from ‘authentic’ student learning activities, may provide new opportunities to receive valuable information on the students' learning behaviors and could be utilised to adjust the learning design already "on the fly" during runtime. We presume that Learning Analytics applied within Learning Design (LD) and presented in a learning dashboard provide opportunities that can lead to more personalized learning experiences, if implemented thoughtfully. In this paper, we describe opportunities and challenges for using LA in LD. We identify three key opportunities for using LA in LD: (O1) using on demand indicators for evidence based decisions on learning design; (O2) intervening during the run-time of a course; and, (O3) increasing student learning outcomes and satisfaction. In order to benefit from these opportunities, several challenges have to be overcome. We mapped the identified opportunities and challenges in a conceptual model that considers the interaction of LA in LD.SURF Foundation & NRO under the REFLECTOR project grant

Computational thermochemistry : extension of Benson group additivity approach to organoboron compounds and reliable predictions of their thermochemical properties

High-level computational data for standard gas phase enthalpies of formation, entropies, and heat capacities are reported for 116 compounds of boron. A comparison of the results with extant experimental and computational benchmark values reveals important trends and clear outliers. Recommendations are made to revise some of the key quantities, such as the enthalpies of formation of orthoboric acid, trimethylthioborate, and triphenylborane, the last of which is found to be considerably in error. The uncertainties associated with the experimental values are found to exceed those of high-level calculations by a clear margin, prompting the redetermination of Benson group additivity contributions for boron-based groups on purely computational grounds. The applicability of the established group contribution values is demonstrated by estimating thermochemical data for large organoboron compounds that cannot be treated with high-level quantum chemical methods and comparing the results with existing experimental and computational values.peerReviewe

High-Level Ab Initio Predictions of Thermochemical Properties of Organosilicon Species : Critical Evaluation of Experimental Data and a Reliable Benchmark Database for Extending Group Additivity Approaches

A high-level composite quantum chemical method, W1X-1, is used herein to calculate the gas-phase standard enthalpy of formation, entropy, and heat capacity of 159 organosilicon compounds. The results set a new benchmark in the field that allows, for the first time, an in-depth assessment of existing experimental data on standard enthalpies of formation, enabling the identification of important trends and possible outliers. The calculated thermochemical data are used to determine Benson group additivity contributions for 60 Benson groups and group pairs involving silicon. These values allow fast and accurate estimation of thermochemical parameters of organosilicon compounds of varying complexity, and the data acquired are used to assess the reliability of experimental work of Voronkov et al. that has been repeatedly criticized by Becerra and Walsh. Recent results from other computational investigations in the field are also carefully discussed through the prism of reported advancements.peerReviewe