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Synlett 1997; 1997(8): 925-928
DOI: 10.1055/s-1997-928
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Isocyanates, Part 4. Convenient Phosgene-Free Method for the Synthesis and Derivatization of Enantiopure α-Isocyanato Carboxylic Acid Esters

Hans-Joachim Knölker* , Tobias Braxmeier
  • *Institut für Organische Chemie, Universität Karlsruhe, Richard-Willstätter-Allee, D-76131 Karlsruhe, Germany, Fax: +49(721)698-529; e-mail: knoe@ochhades.chemie.uni-karlsruhe.de
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Publication Date:
31 December 2000 (online)

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A novel phosgene-free procedure for the synthesis of α-isocyanato carboxylic acid esters starting from α-amino acid esters has been achieved. The isocyanates are obtained enantiomerically pure (>99% ee) by a DMAP-catalyzed isocyanation with di-tert-butyl dicarbonate, which proceeds in 10 min at room temperature. In situ derivatization of the isocyanates by reaction with amines and alcohols affords the corresponding enantiopure ureas and carbamates.

di-tert-butyl dicarbonate - 4-dimethylaminopyridine - α-amino acid esters - α-isocyanato carboxylic acid esters - β-carboline derivatives