Journal ArticleSynthesis of 1,2-Oxazinanes via Hydrogen Bond Mediated [3 + 3] Cycloaddition Reactions of Oxyallyl Cations with NitronesHu, L; Rombola, M.; Rawal, V.H.Smith, Amos B.Reported herein is the development of [3 + 3] cycloaddition reactions between oxyallyl cations and nitrones to yield 1,2-oxazinane heterocycles. Oxyallyl cation intermediates, generated in situ from α-tosyloxy ketones in the presence of hexafluoro-2-propanol (HFIP), a cosolvent, and a base, are found to react with a range of nitrones to afford 1,2-oxazinanes in good to high yields. The reactions are catalyzed by hydrogen-bond donors such as phenols and squaramides, and dramatically higher diastereoselectivities are observed with 4-nitrophenol.2018-08-2210338213Organic letters20175384–53881523-7060https://doi.org/10.1021/acs.orglett.8b023011566402National Science Foundation