A short stereoselective synthesis of racemic 2-epicalvine

摘要

The cycloaddition reaction of 6-pentyl-3,4,5,6-tetrahydropyridine 1-oxide with butyl vinyl ether was used as a key step in the short stereoselective racemic synthesis of ladybird beetle alkaloid, 2-epicalvine. The cycloadduct was subjected to quaternization with 2-bromoethanol, followed by ring opening and lactonization to afford the natural product in a one-pot reaction.