The absolute stereochemistries of (+)-toddalolactone and its related chiral coumarins from Toddalia asiatica(L.) Lam. (T. aculeata Pers.) and their optical purities

Abstract

The absolute stereochemistries of (+)-toddalolactone (+)-1 and its related chiral coumarins [(+)-toddanol (+)-2, (+)-6-(2-hydroxy-3-methoxy-3-methylbutyl)-5,7-dimethoxycoumarin (+)-3, (+)-6-(3-chloro-2-hydroxy-3-methylbutyl)-5,7-dimethoxycoumarin (+)-4 and (–)-aculeatin (–)-5], isolated from Toddalia asiatica(L.) Lam. (T. aculeata Pers.), have been determined as R by ozonolysis of (+)-1 and by the chemical intercorrelation. Their optical purities were estimated by means of an ¹H NMR lanthanoid induced shift study using Eu(hfbc)₃.