Concise syntheses of bis-Strychnos alkaloids (−)-sungucine, (−)-isosungucine, and (−)-strychnogucine B from (−)-strychnine - Zhao, S; Teijaro, C N; Chen, H; Sirasani, G; Vaddypally, S; Zdilla, M J; Dobereiner, G E; Andrade, R B (Chem Weinh Bergstr Ger, 2016)