An asymmetrictotalsynthesis of (+)-chatancin was achieved via a transannularDiels-Alder (TADA) reaction of an in situ generated macrocyclic pyranophane pseudobase. The presented route constitutes the second of two proposed biosynthetic pathways that involves a TADA reaction. It links this diterpene biogenetically to the cembranoids. A set of TADA selection rules that rationalize the formation of
Short, Enantioselective Total Synthesis of Chatancin
作者:Yu-Ming Zhao、Thomas J. Maimone
DOI:10.1002/anie.201410443
日期:2015.1.19
An enantioselectivetotalsynthesis of the polycyclic diterpene (+)‐chatancin, a potent PAF antagonist, is reported. Proceeding in seven steps from dihydrofarnesal, this synthetic route was designed to circumvent macrocyclization‐based strategies to complex, cyclized cembranoids. The described synthesis requires only six chromatographic purifications, is high yielding, and avoids protecting‐group manipulations
A concise and divergent approach for the totalsyntheses of four cembrane diterpenoids, namely (+)‐sarcophytin, (+)‐chatancin, (−)‐3‐oxochatancin, and (−)‐pavidolide B, has been developed, and it also led to the structural revision of (−)‐isosarcophytin. The key steps of the strategy feature a double Mukaiyama Michael addition/elimination, a Helquist annulation, two substrate‐controlled facial‐selective