Studies on difficult intramolecular hydroaminations in the context of four syntheses of alkaloid natural products

J Org Chem. 2013 Dec 20;78(24):12735-49. doi: 10.1021/jo4023149. Epub 2013 Dec 4.

Abstract

Examples of intramolecular alkene hydroaminations forming six-membered ring systems are rare, especially for systems in which the double bond is disubstituted. Such cyclizations have important synthetic relevance. Herein we report a systematic study of these cyclizations using recently developed Cope-type hydroamination methodologies. Difficult intramolecular alkene hydroaminations were used as key steps in syntheses of 2-epi-pumiliotoxin C, coniine, N-norreticuline and desbromoarborescidine A. This effort required the development of optimized hydroamination conditions to improve the efficiency of the cyclizations. Collectively, our results show that Cope-type cyclizations can be achieved on a variety of challenging substrates and proceed under similar conditions for both N-H and N-substituted hydroxylamines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids / chemical synthesis*
  • Alkaloids / chemistry
  • Amination
  • Biological Products / chemical synthesis*
  • Biological Products / chemistry
  • Cyclization
  • Hydroxylamines / chemical synthesis*
  • Hydroxylamines / chemistry
  • Molecular Structure

Substances

  • Alkaloids
  • Biological Products
  • Hydroxylamines