4-Substituted tricyclenes

Clear downfield 8-SCSs (+ 1.3 to + 2.9) were also observed in 4-substituted tricyclenes 122, although they have no syn-axial orientation of X and the 8-carbon atom (154). Possibly, the transmission of the 8-SCS is modulated by the intervening cyclopropane moiety (154). 

The C-NMR of nortricyclene, 2, has been referred to, and Lippmaa reported on a number of derivatives the C-NMR spectrum of quadricyclene, 65, was assigned. The effect of 4-substituents inter alia on the cyclopropyl carbons C(2) and C(6) of 4-substituted tricyclenes (66) showed that there was an essentially linear dependence between SC(2) and... 

Table 1 lists the experimental conditions for the electrochemical formation of a cyclopropyl ring from a variety of 1,3-dihaloalkanes, mostly from dibromoalkyl derivatives. A free cyclopropyl ring as well as a spiro derivative (entry 6), bicyclobutanes (entries 8-10) and other fused and highly strained systems such as tricyclene (entry 11) and a propellane derivative (entries 12,13) were obtained. In addition, Carroll and Peters have found evidence for the intermediacy of [2.2.1 ]propellane upon reducing 1,4-dihalonorbor-nanes electrochemically at a low temperature, although attempts to isolate it were unsuccessful. The intramolecular electrochemical reduction of a dihalo-substituted tricyclic compound leads to cyclization with formation of a tetracyclic derivative in which... 

Arnold, D.R. and Du, X., The photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 5 methanol-monoterpenes (a- and (3-pinene, tricyclene, and nopol), 1,4-dicyanobenzene, Can. J. Chem., 72, 403, 1994. 

The reaction system discussed above was applied to optically pure a-pinene, (3-pinene, tricyclene, and nopol. 4-Cyanophenyl and/or methoxy substituted derivatives in optically pure or racemic mixture forms were isolated as products. Nucleophile-assisted cleavage of the radical cation has been proposed... 

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