PPh3-catalyzed ylide cyclization for the controllable synthesis of benzobicyclo[4.3.0] compounds: base effects and scope
作者:Long-Wu Ye、Xun Han、Xiu-Li Sun、Yong Tang
DOI:10.1016/j.tet.2007.11.052
日期:2008.2
A catalytic intramolecular ylide annulation for the controllable construction of benzobicyclo[4.3.0] ring systems with three continuous stereogenic centers is developed in a single manipulation. In the presence of 20 mol % of triphenylphosphine, the reactions of compounds 1a–1f afford benzobicyclo[4.3.0] compounds 3 and 4 as major products, respectively, with excellent diastereoselectivities in good
通过一次操作开发了可催化构建具有三个连续立体异构中心的苯并双环[4.3.0]环系统的催化分子内叶环氧化。在20摩尔%的三苯膦存在下,化合物1a - 1f的反应分别得到苯并双环[4.3.0]化合物3和4作为主要产物,取决于所用的碱,其非对映异构选择性好,收率高。另外,在相同条件下,2-甲基α,β-不饱和酯2a - 2c也可以很好地产生具有高非对映选择性的具有一个非对映选择性的季碳中心的相应的苯并双环[4.3.0]化合物。