162 research outputs found
Stereospecific Allylic Functionalization:The Reactions of Allylboronate Complexes with Electrophiles
Allylboronic esters react readily with carbonyls and imines (π-electrophiles), but are unreactive toward a range of other electrophiles. By addition of an aryllithium, the corresponding allylboronate complexes display enhanced nucleophilicity, enabling addition to a range of electrophiles (tropylium, benzodithiolylium, activated pyridines, Eschenmoser's salt, Togni's reagent, Selectfluor, diisopropyl azodicarboxylate (DIAD), MeSX) in high regio- and stereocontrol. This protocol provides access to key new functionalities, including quaternary stereogenic centers bearing moieties such as fluorine and the trifluoromethyl group. The allylboronate complexes were determined to be 7 to 10 orders of magnitude more reactive than the parent boronic ester.</p
The implementation of a service-learning component in an organic chemistry laboratory course
Education institutions globally are increasingly expected to explore avenues for the implementation of service-learning into their curricula. A second-year undergraduate organic chemistry laboratory experiment, in which the undergraduate students make azo dyes, can provide a vehicle for a service-learning module in which university undergraduate students then teach students from resource-limited secondary schools how to make azo dyes. Evidence is provided to show how the theory is reinforced for both sets of students through a shared practical experience. The practical application of chemistry is conveyed through the use of the synthetic azo dyes to dye tshirts. The results of this study show that the service-learning experience clearly assists undergraduate students to appreciate the role of chemists in the broader society while at the same time increasing awareness of the inequalities in school education systems
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