Cyclopropane-Annelated Azaoligoheterocycles by Ti-Mediated Intramolecular Reductive Cyclopropanation of Cyclic Amino Acid Amides
作者:Martina Gensini、Armin de Meijere
DOI:10.1002/chem.200305068
日期:2004.2.6
Starting from pyrrole- and indole-2-carboxylic acids 5 a and 5 b, the tri- and tetracyclic N,N-dibenzylcyclopropylamines 7 a and 7 b have been synthesized in 52 and 33 % overall yield, respectively. The synthesis of the enantiopure tetracyclic diamine 10 has been achieved applying the established set of reactions to N-tert-butoxycarbonylindoline-2-carboxylic acid (8) in 46 % overall yield. The amide 15 could