1.
J Antibiot (Tokyo)
; 69(4): 253-8, 2016 04.
Article
in English
| MEDLINE
| ID: mdl-26883393
ABSTRACT
The total syntheses of codonopsinine (1) and 4-epi-codonopsinine (2) were accomplished. The key substituted pyrrole intermediate was constructed via gold-catalyzed addition-cyclization cascade of an aminoacetaldehyde acetal derivative and a terminal alkyne. After diastereoselective reduction of the pyrrole intermediate to the corresponding 3-pyrroline derivative with zinc dust and sulfonic acid, the total synthesis of 4-epi-codonopsinine (2) was achieved via stereoselective construction of the diol by dihydroxylation. In addition, the total synthesis of codonopsinine (1) was completed through stereochemical inversion of the hydroxyl group via epoxide and subsequent ring cleavage under the acidic aqueous condition.