1108. Dehydrohalogenation of the anhydrobromonitrocamphanes

Abstract

The reaction of anhydrobromonitrocamphane (I) or (11) with hydroxylamine gives a saturated oxime (V) which is rapidly dehydrohalogenated. The oxime (V), which retains all the carbon atoms of its progenitor, is an important link in the degradation of the bicyclic system present in compound (I) or (11).Cleavage products of the ketone (VII) are reported.THE stability of bridgehead halides was discovered by Bartlett and Knoxl in a study of apocamphyl chloride. They showed that bridgehead halides are incapable of undergoing bimolecular nucleophilic displacement reactions and that normal elimination reactions of this class of halides fail. Eliel2 has summarized the elimination reactions of bridgehead halides. The solvolysis3 of l-brornobicyclo[2,1,1] hexane yields methylcyclopentadiene by a rearrangement which requires the destruction of the bicyclic system.Forster 4 described the rearrangement of 2-bromo-2-nitrocamphane by concentrated sulphuric acid, and structures for the products, anhydrobromonitrocamphane (I) and anhydrobromonitrocamphane (11) (2-hydroxy-4-bromoapocamphane-l-carbonitrile), were established decisively by van Tamelen and Brenner.5 The P-hydroxy-nitrile (11) was degraded by aqueous alkali to 2,2-dimethyl-3-methylenecyclopentanecarbonitrile (111) , for which the structure was carefully demonst rated.