Stereoselective Introduction of Oxygen Functionalities at the 11/1-Position of Erythrinan Skeleton: Total Syntheses of (±)-Erythristemine and (+)-Erythrartine

Abstract

Oxidation of 8-oxoerythrinan and 8-oxo-1,7-cycloerythrinan derivatives with 2 mol eq of ceric ammonium nitrate in alcohols or acetic acid gave the corresponding 11β-alkoxy or acetoxy compounds in moderate yield. Thus, (±)-3,3,15,16-tetramethoxy-l,7-cycloerythrinan-2,8-dione and (+)-erysotramidine gave the corresponding 11β-methoxy and 11β-acetoxy derivatives on oxidation in methanol and in acetic acid, respectively. Those compounds were respectively converted into (±)-erythristemine and (+)-erythrartine in several steps, thus achieving the total synthesis of these alkaloids. © 1994, The Pharmaceutical Society of Japan. All rights reserved.