Fischer indolization of octahydroindol-6-one derivatives revisited: diastereoisomerization and racemization processes
摘要:
Fischer indolization of enantiopure 2-methoxycarbonyl -cis-octahydroindol-6-ones using AcOH as a catalyst induces racemization of the octahydropyrrolocarbazoles obtained. Conversely, when using TsOH, the alpha-amino ester moiety preserves its configuration, although the other stereogenic centers show a partial or total stereolability according to the constitutional framework. (C) 2008 Elsevier Ltd. All rights reserved.