Intramolecular Condensation via an o-Quinone Methide: Total Synthesis of (±)-Heliol
摘要:
An acid-catalyzed intramolecular [4 + 2] cycloaddition of a non-natural bisabolene is reported. The key cyclocondensation was developed to access cyclic sesquiterpenes from linear phenolic precursors by generating a reactive o-quinone methide intermediate to initiate a cascade reaction. The new method was applied to the first total synthesis of (+/-)-heliol.
Reversal of regiospecificity in the kinetic vs. thermodynamic enolization of bicyclic ketones. Direct bridgehead functionalization of the bicyclo[5.3.1]undecane ring system
作者:Kenneth J. Shea、Steven T. Sakata
DOI:10.1016/s0040-4039(00)74233-x
日期:1992.7
deprotonation of bicyclo [5.3.1] undecenone 3 gives the more highly substituted bridgehead enolate under conditions of kinetic control while the less highly substituted enolate is formed under conditions of thermodynamic control. These findings allow for the direct bridgeheadfunctionalization of this important bicyclic skeleton.