An expeditious and high-yield formal synthesis of hirsutene using Rh(I)-catalyzed [(5+2)+1] cycloaddition

An expeditious and high-yield formal synthesis of hirsutene has been achieved. This synthesis features Rh(I)-catalyzed [(5+2)+1] cycloaddition to construct a bicyclic cyclooctenone, which can be efficiently transformed to bicyclic diketone, an advanced intermediate for racemic and asymmetric syntheses of hirsutene. (C) 2008 Elsevier Ltd. All rights reserved.