Stereocontrolled synthesis of triazacyclopenta[cd]pentalenes by intramolecular 1,3-dipolar cycloaddition reactions of azomethine imines

J Org Chem. 2002 Nov 1;67(22):7880-3. doi: 10.1021/jo026282y.

Abstract

The construction of triazacyclopenta[cd]pentalene diesters 6 by the reaction of dihydropyrrole alpha-ketoesters 3 with acylated hydrazines was evaluated further as a potential central strategic step in the total syntheses of complex guanidine alkaloids such as palau'amine and styloguanidine. Successful cyclocondensations were realized with acid-stable 2,2,2-trichloroethyl carbazate and thiosemicarbazide, but not tert-butyl carbazate. The substituent on the pyrrolidine nitrogen can be alkoxycarbonyl, sulfonyl, or an N-alkyl-2-acylpyrrole group. Siloxy substitution at C1 of the alpha-ketoester side chain is also tolerated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cyclopentanes / chemical synthesis*
  • Cyclopentanes / chemistry*
  • Imines / chemistry*
  • Molecular Structure
  • Stereoisomerism

Substances

  • Cyclopentanes
  • Imines
  • pentalenene