Dedicated to the 50^th anniversary of SYNTHESIS

Abstract

The diterpenoid alkaloids serve as a rich source of synthetic targets for organic chemists, due to the intriguing structure of the overlapping ring systems, along with biological activities commonly associated with compounds of this group. Fifteen total syntheses and numerous synthetic studies towards construction of ring fragments have been reported since 2010. This review article gives a brief overview of diterpenoid alkaloids and summarizes the recent synthetic efforts.

1 Introduction

1.1 Structural Classification and Biosynthetic Origin

1.2 Structure Elucidation of the Aconitum Alkaloids

2 Total Syntheses

2.1 C₁₈-Diterpenoid Alkaloids

2.2 C₁₉-Diterpenoid Alkaloids

2.3 C₂₀-Diterpenoid Alkaloids

3 Strategies To Synthesize Ring Systems

3.1 Radical-Based Cyclizations

3.2 Ruthenium-Mediated Enyne Cycloisomerization

3.3 Reductive Coupling

3.4 Diels–Alder Reactions

3.5 Oxidative Dearomatization/Diels–Alder Sequence

3.6 Transannular Aziridation

3.7 Intramolecular [5+2] Cycloaddition

3.8 Miscellaneous

4 Conclusion

The diterpenoid alkaloids serve as a rich source of synthetic targets for organic chemists, due to the intriguing structure of the overlapping ring systems, along with biological activities commonly associated with compounds of this group. Fifteen total syntheses and numerous synthetic studies towards construction of ring fragments have been reported since 2010. This review article gives a brief overview of diterpenoid alkaloids and summarizes the recent synthetic efforts.

1 Introduction

1.1 Structural Classification and Biosynthetic Origin

1.2 Structure Elucidation of the Aconitum Alkaloids

2 Total Syntheses

2.1 C₁₈-Diterpenoid Alkaloids

2.2 C₁₉-Diterpenoid Alkaloids

2.3 C₂₀-Diterpenoid Alkaloids

3 Strategies To Synthesize Ring Systems

3.1 Radical-Based Cyclizations

3.2 Ruthenium-Mediated Enyne Cycloisomerization

3.3 Reductive Coupling

3.4 Diels–Alder Reactions

3.5 Oxidative Dearomatization/Diels–Alder Sequence

3.6 Transannular Aziridation

3.7 Intramolecular [5+2] Cycloaddition

3.8 Miscellaneous

4 Conclusion