title: Dimethyl dispiro[tricyclo[3.3.1.1(3,7)]-decane-1,2'-bicyclo[1.1.0]butane-4',1"-tricyclo[3.3.1.1(3,7)]decane-1',3'-dicarboxylate, a strain-enhanced bicyclo[1.1.0]butane with a very short intramolecular C--H...H--C contact.
abstract: The title molecule, C(26)H(34)O(4), shows a very short repulsive intramolecular C-H.H-C contact, with an H.H distance of only 1.71 A. The flap angle varphi of the bicyclo[1.1.0]butane group is widened to 131.23 (8) degrees. Both methylene C atoms show tilt angles of 6.1 degrees. Bond lengths in the fused cyclopropane rings range from 1.501 (1) to 1.542 (1) A and are influenced by pi interactions with the carboxylate substituents.
authors: Institut für Organische Chemie, Universität Frankfurt, Marie-Curie-Strasse 11, D-60439 Frankfurt am Main, Germany. bats@chemie.uni-frankfurt.de
authors: J W
authors: JW
authors: Bats
authors: M
authors: M
authors: Bolte
authors: M A
authors: MA
authors: Grundl
authors: A S
authors: AS
authors: Hashmi