An efficient one-potsynthesis of 3,4,5-trisubstituted-3,6-dihydro-2H-1,3-oxazines from acetylene dicarboxylates, aromatic and aliphatic amines, and formaldehyde is described. The six member N,O-heterocyclic nucleus was constructed via Yb(OTf)3 promoted domino hydroamination/Prins reaction/cyclization/dehydration reactions.Graphical Abstract
Synthesis of substituted 1,3-oxazines using sulfamic acid as an efficient and eco-friendly catalyst
作者:M. Damodiran、Paramasivan T. Perumal
DOI:10.1002/jhet.489
日期:2010.11
Sulfamic acid catalyzed the synthesis of substituted 1,3‐oxazines by one‐pot three‐component reaction of aniline, alkynoates, and formaldehyde in excellent yields. The catalyst possesses distinct advantages shows ease of handling, good yields, cleaner reactions, nonhygroscopic, noncorrosive, and high activity. Sulfamic acid is a green alternative for metal‐containing acidic materials, which are toxic