title: 1,7-Dimethyl-penta-cyclo-[5.4.0.0.0.0]undecane-8,11-dione.
abstract: The structure of the title compound, C(13)H(14)O(2), a penta-cyclo-undecane cage derivative, exhibits unusual Csp(3)-Csp(3) single-bond lengths ranging from 1.505 (3) to 1.607 (2) Å and strained bond angles as small as 88.7 (1)° and as large as 121.0 (2)°. In this meso compound, an inter-nal non-crystallographic mirror plane exists, bis-ecting the mol-ecule. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into an infinite spiral about a twofold screw axis along the [100] direction.
authors: Sai Kumar
authors: SK
authors: Chakka
authors: Oluseye K
authors: OK
authors: Onajole
authors: Thavendran
authors: T
authors: Govender
authors: Glenn E M
authors: GE
authors: Maguire
authors: Hong
authors: H
authors: Su
authors: Hendrik G
authors: HG
authors: Kruger
references: Acta Crystallogr C. 2005 Apr;61(Pt 4):o221-6
references: 15805634
references: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references: 18156677