| Sulfur is an element of the Third Period,VI Main Group. Its structure of electron cloud is [Ne]3s23p4. The electronegativity of sulfur is smaller than that of oxygen. The nucleophilicity of sulfur anion is stronger than oxygen anion. Nucleophilic reagent attacks sulfonium ion in Pummerer reaction. This reaction is an important method to synthesize a-sulfur substituted compounds. There’re also many examples in both intermolecular reactions and intramolecular reaction. Pummerer reaction is also helpful to synthesize natural product and complex molecule.Dihydro-oxazole ring is an important unit of many natural products and medicine. It could also be the synthetic precursor of some kinds of organic compounds. N-(2-methyl-3-(4-methylbenzyl)-cyclohex-2-en-l-yl) acetamide is stirred with TFAA under the anhydrous anaerobic condition. We prepared a series of oxazole-derivation. This new method has several advantages, such as, without the participation of metal, facile raw material and good applicability of functional groups.Dihydro-pyrrole/furan-derivations are applied in medicine widely. Triethylamine is used as a base to induce propargyl to turn into allene. Then substrate reacts intramolecular ene reaction and produces dihydro-pyrrole/furan-derivations. This method has several advantages,such as, without the participation of metal, high yield and facile raw material. |
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