2-Bicyclo nonyl systems

Scheme 2.14 Intramolecular TMM [3+2 cycloaddition to bicyclo[4.3.0 nonyl systems...

Gorman and Gassman905 have shown that undecatetraenes undergo cyclization (intramolecular Diels-Alder reaction) in the presence of triflic acid to provide bicyclo[4.3.0]nonyl [Eq. (5.332)], bicyclo[4.4.0]decyl, and bicyclo[5.4.0]undecyl [Eq. (5.333)] ring systems, depending on the methyl-substitution pattern. On the basis of a comparative study with varied tetraenes, they concluded that product formation, at least in some cases, could be best interpreted by a stepwise... 

The relative rates of solvolyses of the four isomeric 2-bicyclo[6.1.0]nonyl 3,5-dinitrobenzoates in 80% aqueous acetone are indicated below . For the cis ring-fused [6.1.0] derivatives 91 and 92, the rates of solvolysis are approximately half as fast as those of the corresponding [5.1.0] derivatives 87 and 88. As observed in the [5.1.0]system, endo... 

A comprehensive NMR spectroscopic study126, of a series of acyclic carbodications was carried out. Carbodications were also observed in more rigid systems, such as the apical, apical congressane dication 57103, bicyclo [2.2.2] octyl dication 65127 and bicyclo [3.3.3] nonyl dication <59106 (manxyl dication — Fig. 10). 

---