title: Two new heterocyclic [3.3.3.01,5]-propellanoid compounds: 2,8-dioxatricyclo[3.3.3.01,5]undecane-3,7-dione and a related dimer.
abstract: 2,8-dioxatricyclo[3.3.3.0(1,5)]undecane-3,7-dione, C(9)H(10)O(4), (I), is the dilactone acylal of cyclopentanone-2,2-diacetic acid. Both molecules in the asymmetric unit have conformational chirality and differ principally in the flexing of the carbon ring, which produces a resolvable conformational disorder in one of the molecules. Three intermolecular C-H...O close contacts exist. 7,7'-Oxybis(2,8-dioxatricyclo[3.3.3.0(1,5)]undecan-3-one), C(18)H(22)O(7), (II), a racemate, lies on a C(2) axis and is a non-meso furanosyl furanoside dimer derived from the monoacid monoaldehyde corresponding to (I). One intermolecular C-H...O close contact exists. Diminished intramolecular void space in these small propellanoids generates unusually high crystal density in both species, particularly (I).
authors.affiliation: Carl A. Olson Memorial Laboratories, Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
authors.forename: Jonglin F
authors.initials: JF
authors.lastname: Tsao
authors.forename: Sana R
authors.initials: SR
authors.lastname: Faruqi
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Thompson
authors.forename: Roger A
authors.initials: RA
authors.lastname: Lalancette