New withanolides from Jaborosa magellanica

Chilean Jaborosa magellanica has supplied a series of four new withanolides that incorporate a γ-lactone side chain as well as an extra hemiketalic ring. These withanolides are(-)-jaborotetrol {1}, (-)-jaborolone {5}, and the chlorinated (+)-jaborochlorotriol {6} and (-)-jaborochlorodiol {8}. A newly found pair of withanolides possessing a δ-lactone side chain are (+)-jaboromagellone {11} and (+)-projaborol {9}. The latter could function as a possible precursor for the previously known (+)-jaborol {10}