An Asymmetric Synthesis and Absolute Configuration of (S)-(-)-Deplancheine

Article abstract of DOI:10.1021/jo00366a005

An asymmetric synthesis of (S)-(-)-deplancheine has been achieved in 96.5percent ee via the chiral valine-based formamidine 8 of β-carboline.Alkylation of the latter, via its lithio salt, with the appropriate alkyl bromide 19c gave the highly enantioenriched intermediate 20, which was carried forward to the title product.On the basis of the stereochemical properties of deplancheine, the original assignment of absolute configuration (S) has now been reassigned as R-(+)