Synthesis of (±)- and (−)-botryodiplodin using stereoselective radical cyclizations of acyclic esters and acetals
作者:Robert Nouguier、Stéphane Gastaldi、Didier Stien、Michèle Bertrand、Félix Villar、Olivier Andrey、Philippe Renaud
DOI:10.1016/j.tetasy.2003.06.004
日期:2003.10
Three different routes for the stereoselective synthesis 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
已经研究了用于葡萄孢菌素的立体选择性合成的三种不同途径。缩醛的分子内烯丙基化由于不稳定的中间体和差的立体控制而被证明是不令人满意的。2-碘代丙酸酯衍生物的Zard分子内自由基烯丙基化可以快速发展外消旋的葡萄孢单倍体。最终产品中的相对构型已通过去质子-再质子化步骤进行了校正。接下来研究了烯丙基溴缩醛的环化反应,证明其对于合成外消旋和对映体纯的葡萄球菌双孢菌素是令人满意的。通过环化宝石-二溴化物,然后立体选择性地还原由此形成的环状一溴化物,实现了良好的立体控制。