research papers
A cocrystal, obtained from Drimys winteri, is composed of two isomeric drimane sesquiterpene lactones, namely valdiviolide and 11-epivaldiviolide, neither of which has been reported in the crystal form. Both diastereoisomers present three chiral centres at sites 5, 10 and 11, with an SSR sequence in (Ia) and an SSS sequence in (Ib).