2- Bicyclo heptyl 3,5-dinitrobenzoates

For the various methyl-substituted 2-bicyclo[4.1.0]heptyl 3,5-dinitrobenzoates , in all cases the exo isomers were slightly more reactive than the endo. The k Jky values for the various methyl substituents, which were as expected based on studies involving open-chain cyclopropylcarbinyl systems were 1-methyl = 2 2-methyl = 10 6-methyl = 10 antz-7-methyl = 6. In a study using a 1-phenyl substituent a rate decrease by a factor of about 10 was observed. This may be due in part to electron-withdrawing inductive effects of the phenyl group and in part to steric hindrance to solvation for the cyclopropylcarbinyl system. 

The hydrolysis products in 80% acetone for the 1-methyl-substituted 2-bicyclo[4.1.0]heptyl 3,5-dinitrobenzoates were not markedly different from those of the parent system. However, substitution of 6- and 7-methyl groups as well as a 1-phenyl groupsor a 1-isobutoxy groupsproduced major changes in product distributions as shown in Scheme 13. 

SCHEME 13. Effects of substituents on product distributions from hydrolysis of 2-bicyclo[4.1.0]heptyl 3,5-dinitrobenzoates... 

Finally, several systems which are more commonly thought of as dehydroadamantyl or dehydrohomoadamantyl systems may also be considered as 2-bicyclo[4.1.0]heptyl derivatives. For the case of the 8,9-dehydro-2-adamantyl 3,5-dinitrobenzoate (85),... 

The first studies in the 2-bicyclo[5.1.0]octyl system were reported by Cope and coworkers . However, they did not measure any reaction kinetics, and product studies were done under conditions where the initial products were not stable. Later in 1969, Friedrich and Wight studied the rates and products of hydrolyses of the endo- and exo-2-bicyclo[5.1.0]octyl 3,5-dinitrobenzoates 87 and 88 in 80% acetone. In contrast to the behavior seen with the [3.1.0]hexyl and [4.1.0]heptyl systems where rates and products are essentially independent of leaving group stereochemistry, the em/o-2-bicyclo[5.1.0]octyl 3,5-dinitrobenzoate (87) reacts 24 times faster than does the exo isomer (88). Both are. 

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