Synthesis of the Quinolizidine Alkaloids (−)-Lasubine II and (±)-Myrtine by Conjugate Addition and Intramolecular Acylation of Amino Esters with Acetylenic Sulfones
作者:Thomas G. Back、Michael D. Hamilton、Vania J. J. Lim、Masood Parvez
DOI:10.1021/jo048284j
日期:2005.2.1
The conjugate additions of (2-piperidyl)acetate esters to acetylenic sulfones, followed by LDA-promoted intramolecular acylations, afforded cyclic enaminones that were readily converted into the corresponding 4-substituted 2-keto- or 2-hydroxyquinolizidines by stereoselective reduction and desulfonylation. This procedure was applied to the total synthesis of (−)-lasubine II from methyl (S)-(2-piperidyl)acetate
将(2-哌啶基)乙酸酯共轭加成到乙炔砜中,然后LDA促进分子内酰化,得到的环烯胺酮可通过立体选择性还原和脱磺酰基反应容易地转化为相应的4-取代的2-酮或2-羟基喹oli嗪。该步骤应用于由(S)-(2-哌啶基)乙酸甲酯和2-(3,4-二甲氧基苯基)-1-(对甲苯磺酰基)乙炔的(-)-lasubine II的全合成。类似地,(±)-(2-哌啶基)乙酸甲酯和1-(对甲苯磺酰基)丙炔提供了(±)-肉豆蔻。