The crystal and molecular structure of trans-dimethyl 2 alpha-methyl(3 alpha H) perhydro [1,2]oxazolo-[2,3-a]azepine-2 alpha,3 alpha-dicarboxylate: A7/5-fused ring system

The title compound crystallizes in the monoclinic space group P2(1)/n, with a = 6.225(1), b = 14.612 (1), c = 15.520 (1) Angstrom, beta = 96.6(3)degre es, Z = 4 and V = 1402.4 Angstrom(3). The stereochemistry of the 7/5-fused ring system is trans, the 7-membered and the 5-membered rings are found to be in the chair and envelope conformations, respectively. This represents t he first study of a compound containing the 7/5-ring skeleton shown in (3) below.