Crystal structures of two lactones of the bicyclo[2,2,2]octane series

Abstract

The crystal structures of two γ-lactones of the bicyclo[2,2,2]octane series, endo-3-carboxy-exo-5- iodobicyclo[2,2,2]octane-2,6-carbolactone (2; R = CO₂H) and exo-3-methoxycarbonyl-endo-5-acetoxybicyclo[2,2,2] octane-2,6-carbolactone (7b), have been determined by direct methods from three-dimensional X-ray data and refined by least-squares to final residuals of 0.033 (2; R = CO₂H) and 0.036 (7b) for 1918 and 630 'observed' reflections respectively. Crystals for (2; R = CO₂H) are monoclinic, space group P2₁/c with Z 8 in a cell of dimensions a 7.192(2), b 23.785(8), c 13.199(5) Å, β 105.35(2)º, while (7b) crystallizes in the orthorhombic space group P2₁2₁2₁ with Z 4 in a cell of dimensions a 13.347(7), b 11.839(7), c 8.227(11) Å.