Synlett 2005(1): 1-25  
DOI: 10.1055/s-2004-834813
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

Recent Advances in the Synthesis of Angucyclines

M. Carmen Carreño*, Antonio Urbano
Departamento de Química Orgánica (C-I), Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain
Fax: +34(914)973966; e-Mail: carmen.carrenno@uam.es;
Further Information

Publication History

Received 20 May 2004
Publication Date:
20 October 2004 (online)

Abstract

The different strategies recently reported to construct the tetracyclic skeleton of angucyclines are presented: Diels-Alder and Friedel-Crafts reactions, nucleophilic additions, free radical annulations, rearrangements of cyclobutenones and cobalt-mediated [2+2+2] cycloadditions. Among the asymmetric approaches, the most efficient corresponds to Diels-Alder reactions including the use of chiral catalysts, enantiopure vinyl cyclohexenes as dienes, synthesized from quinic acid or (S,S)-[(p-tolylsulfinyl)methyl]-p-quinol, and chiral dienophiles such as (S,S)-2-(p-tolylsulfinyl)-1,4-naphthoquinones.

  • 1 Introduction

  • 2 Diels-Alder Reactions

  • 2.1 Formation of B Ring: DC+A Strategy

  • 2.2 Formation of C Ring: D+BA Strategy

  • 2.3 Formation of D Ring from a Dienophile Bearing the CBA Moiety

  • 3 Friedel-Crafts Reactions

  • 4 Nucleophilic Additions

  • 4.1 Anionic Annulations with Phthalides

  • 4.2 Other Anionic Annulations

  • 5 Free Radical Annulations

  • 6 Rearrangements of Cyclobutenones

  • 7 Cobalt-Mediated [2+2+2] Cycloadditions

  • 8 Summary

36

For a detailed discussion of the possible transition states see ref. 33.