1,745 research outputs found
Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes
A new family of carbohydrate-based dihydroisoquinolinium salts has been prepared and tested for potential as asymmetric catalysts for the epoxidation of unfunctionalized alkene substrates, providing up to 57% ee in the product epoxides
Unexpected nucleophilic participation and rearrangement of DBU in reactions with saccharin derivatives
DBU attacks saccharin derivatives with subsequent rearrangement to give rise to 3-[3'-(1"-azepin-2"-onyl)propylamino]-1,2-benzisothiazole-1,1-dioxide 2 after work-up
Social Justice and Social Order: Binding Moralities across the Political Spectrum
Two studies explored the relationship between political ideology and endorsement of a range of moral principles. Political liberals and conservatives did not differ on intrapersonal or interpersonal moralities, which require self-regulation. However differences emerged on collective moralities, which involve social regulation. Contrary to Moral Foundations Theory, both liberals and conservatives endorsed a group-focused binding morality, specifically Social Justice and Social Order respectively. Libertarians were the group without a binding morality. Although Social Justice and Social Order appear conflictual, analyses based on earlier cross-cultural work on societal tightness-looseness suggest that countries actually benefit in terms of economic success and societal well-being when these group-based moralities co-exist and serve as counterweights in social regulation
Ultra-Wideband Communication and Sensor Fusion Platform for the Purpose of Multi-Perspective Localization.
Localization is a keystone for a robot to work within its environment and with other robots. There have been many methods used to solve this problem. This paper deals with the use of beacon-based localization to answer the research question: Can ultra-wideband technology be used to effectively localize a robot with sensor fusion? This paper has developed an innovative solution for creating a sensor fusion platform that uses ultra-wideband communication as a localization method to allow an environment to be perceived and inspected in three dimensions from multiple perspectives simultaneously. A series of contributions have been presented, supported by an in-depth literature review regarding topics in this field of knowledge. The proposed method was then designed, built, and tested successfully in two different environments exceeding its required tolerances. The result of the testing and the ideas formulated throughout the paper were discussed and future work outlined on how to build upon this work in potential academic papers and projects
New biphenyl iminium salt catalysts for highly enantioselective asymmetric epoxidation: role of additional substitution and dihedral angle
New biaryl iminium salt catalysts for enantioselective alkene epoxidation containing additional substitution in the heterocyclic ring are reported. The effects upon conformation and enantioselectivity of this additional substitution, and the influence of dihedral angle in these systems, has been investigated using a synthetic approach supported by density functional theory. Enantioselectivities of up to 97% ee were observed
Asymmetric epoxidation of chromenes mediated by iminium salts: Synthesis of mollugin and (3S,4R)-trans-3,4-dihydroxy-3,4-dihydromollugin
Organocatalytic asymmetric epoxidation of chromenes mediated by iminium salt catalysts under non-aqueous conditions provided ees as high as 99%. Contrastingly, reaction under aqueous conditions can form the corresponding diol products with ees as high as 71%. The process has been used for the synthesis of the East African medicinal plant metabolite (3S,4R)-trans-3,4-dihydroxy-3,4-dihydromollugin
Kinetic Resolution in Asymmetric Epoxidation using Iminium Salt Catalysis
The first reported examples of kinetic resolution in epoxidation reactions using iminium salt catalysis are described, providing up to 99% ee in the epoxidation of racemic cis-chromenes
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