Synthesis of racemic and enantiopure 3,4-methanonipecotic acid
摘要:
The synthesis of both racemic and enantiomerically pure (1R,6S)-3,4-methanonipecotic acid, a cyclopropane-containing 8-amino acid, which is a valuable building block for drug discovery, is described. The synthetic scheme commences from natural (S)-malic acid and allows for the preparation of the title compound in 12 steps in 28% overall yield. A novel approach to the racemic 3,4-methanonipecotic acid, which relies on a Simmons-Smith cyclopropanation as the key step, was also developed. In this case, the product was obtained in 8 steps and 38% total yield. (C) 2015 Published by Elsevier Ltd.
A full study on the synthesis of 3-azabicyclo[4.1.0]heptane-1-carboxylic acid is described. Three different approaches were investigated in order to achieve an efficient synthesis of this unnatural aminoacid. The optimized synthetic route relies upon three key steps: (i) diazomalonate insertion on 4-phtalimido 1-butene, (ii) intramolecular cyclization and (iii) chemoselective reduction of the resulting