Convenient preparative synthesis of pentacyclo[5.3.0.02,5.03,9.04,8]decane (C 2-Bishomocubane)

Abstract

By reaction of pentacyclo[5.3.0.0 2,5 .0 3,9 .0 4,8 ]decane-6,10-dione 6-ethyleneketal with lithium aluminum hydride the corresponding hydroxyketal was obtained whose hydroxy group was replaced by chlorine at boiling in CCl 4 in the presence of a 15% molar excess of triphenylphosphine. 6-Ethyleneketal of pentacyclo-[5.3.0.0 2,5 .0 3,9 .0 4,8 ]decan-6-one obtained by dechlorination of the chloroketal in a system lithium-t-BuOH in THF was hydrolyzed to ketone by heating in 10% sulfuric acid in the presence of THF. The obtained ketone was reduced along Wolf-Kishner reaction to pentacyclo[5.3.0.0 2,5 .0 3,9 .0 4,8 ]decane.

Selective reductive dimerization of homocubane series oximes

“…Dibromomethane was distilled off in a vacuum of a water-jet pump, the residue was treated with boiling hexane (4 × 75 ml), hexane was evaporated in a vacuum, and the residue was subjected to column chromatography on silica gel, eluent hexane-ethyl ether, [28]. Yield 5.6 g (95%), bp 123-126°С (14 mm Hg) [26]. Spectral characteristics were identical to published in [29].…”

“…13 С NMR spectrum of amine XIІb contains a large number of signals of various intensity complicating its structural analysis. Actually, pentacyclo[5.3.0.0 2,5 .0 3,9 .0 4,8 ] decane (С 2 -bisnomocubane), substituted at the secondary carbon atom exists in the form of sуn-and anti-epimers with the latter usually prevailing [25,26]. It is presumable that amine XIІb forms as three isomers as confi rmed by the presence in the 13 С NMR spectrum of three pairs of carbon nuclei signals with the intensity ratio ~9:3:1 in the region of 66 ppm, belonging to carbon atoms attached to the nitrogen atom.…”