Recent Developments with Icetexane Natural Products

Abstract

Icetexane diterpenoids are a diverse family of natural products sourced from several species of terrestrial plants. Icetexanes exhibit a broad array of biological activities and together with their complex 6‐7‐6 tricyclic scaffolds, they have piqued the interest of synthetic organic chemists, natural products chemists, and biological investigators over the past four decades and were reviewed 13 years ago. This review summarizes icetexane natural products isolated since 2009, provides an overview of new synthetic approaches to the icetexane problem, and proposes an additional classification of icetexanes based on novel structures that are unlike previously isolated materials.

A Newabeo‐Icetexane‐Type Diterpenoid from the Stem Barks ofTaxus wallichiana

“…In this study, taxamairin I was proposed to be derived from taxusabietane A followed by many bond migrations. Taxamairin I represents the first naturally occurring example of a 6‐6‐6 tricyclic skeleton of abeo ‐icetexane diterpenoid [20,23,24] . The absolute configuration of the chiral carbon C‐13 of taxamairin I was identified based on the TD‐DFT optical rotation calculation.…”

“…Taxamairin I represents the first naturally occurring example of a 6-6-6 tricyclic skeleton of abeo-icetexane diterpenoid. [20,23,24] The absolute configuration of the chiral carbon C-13 of taxamairin I was identified based on the TD-DFT optical rotation calculation. In addition, taxamairin I did not show cytotoxicity against Hep3B human liver cancer cells.…”

Total Synthesis of Brevitaxin

“…In recent decades, more than 100 novel icetexanes with the 9(10 → 20)-abeo-abietane skeleton have been isolated from medicinal plants of the genus Salvia . These have attracted considerable attention of the synthetic chemistry community because of their specific structures and potential antitumor activities. − Brevitaxin ( 1 ) was initially isolated as a racemate in a meager yield of 0.00009% by Arslanian et al in 1995 .…”