2-Hydroxy-3-aryl morpholines are readily prepared from arylboronic acids, aqueous glyoxal, and 1,2-aminoethanols by a variant of the Petasis borono-Mannich reaction. We now show that the 2-hydroxy-3-aryl morpholines may be deoxygenated to 3-aryl morpholines by treatment with methanesulfonic anhydride and triethylamine to afford intermediate 3,4-dihydro-2H-1,4-oxazines, followed by reaction with a triacetoxyborohydride salt and acetic acid to afford 3-aryl morpholines. This reaction sequence constitutes a three step, “two pot” preparation of 3-aryl morpholines from readily available starting materials (1,2-aminoethanols, arylboronic acids, and glyoxal) with excellent functional group tolerance and adaptability to scale.

通过Petasis borono-Mannich反应的一种变体，可以从芳基硼酸，含水乙二醛和1,2-氨基乙醇轻松制备2-羟基-3-芳基吗啉。我们现在表明，可以通过用甲磺酸酐和三乙胺处理将2-羟基-3-芳基吗啉脱氧为3-芳基吗啉，以提供中间体3,4-二氢-2 H -1,4-恶嗪，然后与用三乙酰氧基硼氢化盐和乙酸制得3-芳基吗啉。该反应序列由容易获得的起始材料（1,2-氨基乙醇，芳基硼酸和乙二醛）组成的三步“两锅”制备3-芳基吗啉，具有优异的官能团耐受性和规模适应性。