The crystal structure of a novel bicyclic lactone derivative containing a ?Chiral Malonate? Unit

Abstract

Crystals of the phenylurethane derivative of a novel bicyclic lactone, C18H21NO8, have an orthorhombic unit cell of dimensionsa = 8.648(2),b = 11.041(7),c = 19.589(4) A, and belong to space groupP212121. The structure was solved by direct methods and was refined by the block diagonal approximation to a finalR value of 0.034 using 1035 reflections. The structure is made up of a six-membered lactone ring, in the boat conformation,cis-fused to a five-membered oxolane ring. The phenylurethane and the methoxy groups aretrans to each other, while the ethyl carboxylate group is attached in equatorial position.