Bridged Polycyclic Compounds

It has been found empirically that central analgesics that possess some degree of activity as antagonists of the effects of morphine tend to show a reduced propensity for causing physical addiction. Again empirically, it was noted that this could often be achieved by replacement of the N-methyl group by allyl, cyclopropylmethyl, or cyclobutylmethyl additional nuclear modifications often contributed to this activity. 

Replacement of the alicyclic ring of morphine in addition to omission of the furan ring leads to a thoroughly investigated series of analgesic compounds known as the 

A rather unusual reaction forms the key step in the preparation of a benzomorphan bearing a fatty side chain, The scheme used to form the benzomorphan nucleus, which is patterned after the Grewe synthesis originally developed for 

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Intramolecular reactions of electron donor and acceptor sites in cyclic starting materials produce spirocyclic, fused, or bridged polycyclic compounds. 

Twistane, as an example of a non-natural product, which is a chiral, bridged polycyclic compound, completely deprived of functionality. 

Electron transfer may also be important in a series of photosolvolysis/rearrangement of certain bridged polycyclic compounds. The efficiency of photochemically induced solvolyses (186), for example eq. 60,... 

Compounds in which ring heteroatoms are members of another fused ring and bridged polycyclic compounds are, with a few exceptions, not covered in this chapter. 

Mekenyan, G., Bonchev, D. and Trinajstic, N. (1981). Algebraic Characterization of Bridged Polycyclic Compounds. InU.QuaniChem., 19, 929-955. 

Chenier, P. J. The Favorskii rearrangement in bridged polycyclic compounds. J. Chem. Educ. 1978, 55, 286-291. 

A logical extension of this strategy, particularly important for bridged polycyclic compounds, is the common atom approach. Atoms common to two or more rings (the common atoms) are marked disconnections of bonds to these atoms must inevitably reduce the number of rings. 

Cristol, S. J., Sequeira, R. M., DePuy, C. H. (1965). Bridged Polycyclic Compounds. XXXI. Stereochemical Aspects of the Solvolysis of Cyclopropyl Chloridesl. Journal of the American Chemical Society, 87, 4007-4008. 

Aside from the aforementioned demanding examples, the 6-exo-trig Mizoroki-Heck cyclization also allows for the formation of bridged polycyclic compounds (Scheme 5.27). Vinyl iodide 144 was cyclized in good yield and produced 145 as a 9 1 mixture of doublebond isomers (minor isomer not shown) (144 145) [21]. The analogous aryl iodide (not shown) furnished in the presence of 5 mol% (Ph3P)4Pd the product in 81% yield, but in a 7 3 mixture of double-bond isomers. Coe et al. [69] used the Mizoroki-Heck reaction... 

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