(1S*, 4S*, 5R*, 6S* ,8S*, 11R*)-5,6-Epoxy-1-hydroxy-6-isopropyl-3,11- dimethyl-3-azatricyclo-[6.2.1.0(4,11)]undecan-2-one, C15H23NO3, Mr = 265.35, triclinic, P1, a = 7.2170 (6), b = 8.5578 (10), c = 12.4342 (14) A, alpha = 97.017 (9), beta = 91.733 (8), gamma = 109.799 (8) degree, V = 715.04 (13) A3, Z = 2, D chi = 1.23 g cm-3 (298 K), lambda(Mo K alpha) = 0.7107 A, mu = 0.7949 cm-1, F(000) = 288, T = 298 K, R = 0.0482 for 2464 reflections. The molecules exist as hydrogen-bonded dimers in the crystal involving the hydroxyl group and the carbonyl O atom [O13...O14 (related by 2 - x, - y, - z) 2.719 (2) A; H13...O14 1.90 (2) A; O13--H13...O14 165 (2) degrees]. The bonds from the bridgehead atom of the tricyclic ring to other ring atoms appears to be elongated [av. 1.557 (1) A] compared to the other Csp3--Csp3 bonds in the molecule. The lactam ring is essentially planar [maximum deviation is 0.010 (3) A for N3].