Crystal structure of (1R,3S,8R,11R)-11-acetyl-3,7,7-trimethyl-10-oxatri-cyclo-[6.4.0.0(1,3)]dodecan-9-one.

The title compound, C16H24O3, is built up from three fused rings, a six-membered, a seven-membered and a three-membered ring. The absolute configuration of the title compound was determined as (1R,3S,8R,11R) based on the synthetic pathway. The six-membered ring has an half-chair conformation whereas the seven-membered ring displays a boat conformation. In the cyrstal, C-H⋯O hydrogen bonds build up a two-dimensional network parallel to (0 0 1). The crystal studied was an inversion twin with a minor twin component of 34%.