aDepart. de Q. Inorgánica y Orgánica, Univ. Jaume I, Castellón, E-12080 Castellón, Spain
bDepart. de Q. Orgánica, Univ. de Valencia, E-46100 Burjassot, Valencia, Spain
Abstract:
The first stereoselective syntheses of the naturally occurring, ,β-unsaturated lactone hyptolide 1 and of its nonnatural epimer at C-6 are described. Ethyl l-lactate was the chiral starting material. Key steps of these syntheses were a Brown's asymmetric allylation, a Carreira's asymmetric ethynylation and a ring closing metathesis.