Synthetic applications of 2-(1,3-dithian-2-yl)indoles. IV. New synthesis of the tetracyclic ABED ring system of Strychnos alkaloids
作者:Anna Diez、Josep Castells、Pilar Forns、Mario Rubiralta、David S. Grierson、Henri-Philippe Husson、Xavier Solans、Mercè Font-Bardía
DOI:10.1016/s0040-4020(01)89689-7
日期:——
A new and versatile synthesis of tetracyclic compounds 10, 22 and 24 presenting the ABED ring system of Strychnos alkaloids is described by closure of the C1C11b bond in the key step. The intermediate tetrahydropyridinium salts 2 have been obtained from 2-(1,3-dithian-2-yl)indole (3) and either 2-cyano-3-ethyl-1-methyl-1,2,3,6-tetrahydropyridine (4a) or N-substituted Δ3-piperidein-2-ones (5).