Chemoselective protection of alpha-ketoacids by direct annulations with oximes

Construction of 3-Oxazolin-5-one via Visible Light-Induced Nondecarboxylative Coupling and Sequential Reactions

3-Oxazolin-5-ones are precursors of nitrile ylides and represent valuable 1,3-dipoles for constructing cyclic imines or pyrrole compounds. Harnessing the power of photocatalysis, we accomplished a straightforward synthesis of 3-oxazolin-5-ones from redox-active esters and secondary nitro compounds. Visible light-induced nondecarboxylative coupling of a redox-active ester, nitro aldol condensation, and subsequent visible light-induced N-oxide deoxygenation were accomplished within 2 h. The reaction mechanism was supported by experimental data and DFT calculations.

Synthesis and Transformations of Nitrones for Organic Synthesis

Nitrones are important compounds and are highly useful in many aspects. The first part describes the methods for synthesis of nitrones, which are useful and environmentally friendly. Catalytic oxidations, condensations, and other useful reactions are described. The nitrones thus obtained are key intermediates for the synthesis of biologically important nitrogen compounds. The second part describes the fundamental transformations of nitrones, which will provide the strategies and means for the construction of nitrogen compounds. The reactions with nucleophiles or radicals, C-H functionalization, and various addition reactions are described. The last reactions are particularly important for highly selective carbon-carbon bond formations. 1,3-Dipolar cycloaddition reactions are excluded because the size of the review is limited and excellent reviews have been published in Chemical Reviews.