[Show abstract][Hide abstract] ABSTRACT: A Web-based resource has been developed to assist instructors of organic spectroscopy courses. This Web site is populated by NMR FID files that can be freely downloaded by registered users. Current offerings include FID files for 1H and 13C NMR, DEPT, 1H–1H COSY, HMQC, HMBC, TOCSY, and 1D NOE experiments. External users can also submit their own data for use by other instructors. By supplying users with the FID files, it will be easier for them to emphasize certain areas of the spectrum for use during in-class discussions, problem sets, and exams.
Journal of chemical education 07/2013; 90(7):941-943. · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of ligand and substrate choice on the Pd-catalyzed cyclization of alkyne-tethered cyclohexadienones were examined. In the presence of a chiral ligand, the enantioselectivity of the desymmetrization is remarkably sensitive to structural changes in both the ligand and the substrate. Additionally, the regioselectivity of the reaction (5- vs. 6-membered ring formation) is dependent on the proximity of heteroatoms to the alkyne.
[Show abstract][Hide abstract] ABSTRACT: The cyclization of 2,5-cyclohexadienones tethered to activated methylene groups was studied. The substitution around the cyclohexadienone ring serves to regioselectively direct these cyclizations based primarily on electronic effects. In the case of brominated substrates, these reactions proceed to give highly unusual electron-deficient tricyclic cyclopropanes. By using a Cinchona alkaloid-based phase-transfer catalyst, prochiral cyclohexadienones can be desymmetrized with moderate stereoselectivity.