Diastereoselective radical cyclization of bromoacetals: Efficient synthesis of (±)-botryodiplodin
作者:Fe´lix Villar、Olivier Andrey、Philippe Renaud
DOI:10.1016/s0040-4039(99)00487-6
日期:1999.4
A stereoselective synthesis of (±)-botryodiplodin is presented. The key reaction is a radical cyclization of a bromoacetal (Ueno-Stork reaction). The stereogenic acetal center has been used to control the stereoselectivity of the process: the difficulty in controlling the stereochemistry at C(3) of the tetrahydrofuran moiety during the cyclization step has been overcome by a double one-pot reduction
Three different routes for the stereoselectivesynthesis of botryodiplodin have been investigated. The intramolecular allylation of acetals proved to be unsatisfactory due to unstable intermediates and poor stereocontrol. Zard intramolecular radical allylation of a 2-iodopropionate derivative allows the development of an expeditious synthesis of racemic botryodiplodin. The relative configuration within