Synthesis of 1,2-Oxazinanes via Hydrogen Bond Mediated [3 + 3] Cycloaddition Reactions of Oxyallyl Cations with Nitrones
Synthesis of 1,2-Oxazinanes via Hydrogen Bond Mediated [3 + 3] Cycloaddition Reactions of Oxyallyl Cations with Nitrones
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氢键介导的 1,2-恶嗪烷合成 [3 3] 草烯丙基阳离子与硝酮的环加成反应
DOI：
10.1021/acs.orglett.8b02301
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发表时间：
2018
期刊：
影响因子：
5.2
通讯作者：
Rawal, V.H.
中科院分区：
文献类型：
--
作者：
Rombola, M.;Rawal, V.H.
本文报道了氧基烯丙基阳离子与硝酮进行[3+3]环加成反应合成1，2-恶杂环的研究进展。在六氟-2-丙醇、助溶剂和碱的存在下，α-对甲苯磺氧基酮生成的氧烯丙基阳离子中间体与一系列硝酮反应生成1，2-恶嗪烷。这些反应是由氢键供体如苯酚和方酰胺催化的，而4-硝基苯酚的非对映选择性要高得多。
Reported herein is the development of [3 + 3] cycloaddition reactions between oxyallyl cations and nitrones to yield 1,2-oxazinane heterocycles. Oxyallyl cation intermediates, generatedin situfrom 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.