A new approach to the synthesis of carbamates based on a tin-catalyzed transcarbamoylation process has been developed. Reactions of primary and secondary alcohols with phenyl carbamate in toluene at 90 °C proceed smoothly in the presence of tin-catalyst to generate the corresponding carbamates in good yields. This mild method exhibits a broad functional-group tolerance.
已经开发了一种基于锡催化氨基甲酰化过程合成氨基甲酸酯的新方法。伯醇和仲醇与氨基甲酸苯酯在 90 °C 的甲苯中在锡催化剂存在下顺利进行反应,以良好的产率生成相应的氨基甲酸酯。这种温和的方法表现出广泛的官能团耐受性。
Iron-Catalyzed Reaction of Urea with Alcohols and Amines: A Safe Alternative for the Synthesis of Primary Carbamates
A general study of the iron‐catalyzedreaction of urea with nucleophiles is here presented. The carbamoylation of alcohols allows for the synthesis of N‐unsubstituted (primary) carbamates, including present drugs (Felbamate and Meprobamate), without the necessity to apply phosgene and related derivatives. Using amines as nucleophiles gave rise to the respective mono‐ and disubstituted ureas via selective
The use of palladium to effect two different reactions on a common starting material is presented. With a copper oxidant, an aminohalogenation is achieved to produce oxazolidinones. When the copper is absent, a [3,3]-sigmatropic rearrangement takes place to produce allylic amides.
SnCl2-catalyzed synthesis of carbamates from renewable origin alcohols
作者:Márcio José da Silva、Diego Morais Chaves
DOI:10.1007/s11696-017-0349-7
日期:2018.5
suitable method for the synthesis of carbamates from renewable origin alcohols and urea in one-step are provided. We have assessed the activity of SnCl2 catalyst, a commercially affordable Lewis acid, in reactions of urea alcoholysis with different natural origin alcohols (geranyl, neryl, bornyl, cinnamyl, α-terpinyl and benzyl alcohols), aiming to synthesize carbamates, which are biologically active compounds
A diastereoselective aminohydroxylation of olefins with a functionalized hydroxylamine is catalyzed by new iron(II) complexes. This efficient intramolecular process readily affords synthetically useful amino alcohols with excellent selectivity (dr up to > 20:1). Asymmetric catalysis with chiral iron(II) complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.