Synthesis of C4C5 Cycloalkyl-Fused and C6-Modified Chromans via<i>ortho</i>-Quinone Methides
作者:Kassrin Tangdenpaisal、Kanokpish Chuayboonsong、Patchaya Sukjarean、Varisa Katesampao、Nok Noiphrom、Somsak Ruchirawat、Poonsakdi Ploypradith
DOI:10.1002/asia.201403356
日期:2015.4
from 3,5‐dimethoxybenzaldehyde, some functionalized 2,3,4‐trisubstituted tricyclic 4,5‐cycloalkyl‐fused and 6‐modified chromans could be prepared via ortho‐quinone methides (o‐QMs)/hetero‐Diels–Alder (HDA) reactions of the appropriate precursors. The bromide at C6 served as a handle for introducing other substituents through palladium‐catalyzed cross‐coupling reactions and other functional‐group transformations
从3,5-二甲氧基苯甲醛开始,可以通过邻醌甲基(o -QMs)/杂Diels-Alder( HDA)适当前体的反应。C6处的溴化物可作为通过钯催化的交叉偶联反应和其他官能团转化引入其他取代基的方法。在[PtCl 4 ]催化下可获得中等至高产率(高达80%)和非对映选择性(高达> 99:1)。优选内切环加成反应中的过渡态中管理在C2的立体化学结果起到了重要作用 C3 C4。在构型上固定Ë双环的几何ö -QMs影响了环加成反应,以有利于C2 C4顺式关系。