Bicyclo undecane group

Deprotonation of the dication cij-1,6-dimethyl-l,6-diazoniabicyclo[4.4.0]decane (66) results in products derived from deprotonation at a methyl group, including 1-methyl-l-azonia-6-bicyclo[4.4.1]undecane (67) <84JCS(P2)4ll, 86J0C3169>, and deprotonation of the dication of 6-methyl-l,6-diazoniatricyclo[6.2.2.0 ]dodecane (68) affords the monoion of 1-methyl-l-azonia-6-aza-tricyclo[7.2.1.0 "]dodecane (69) <86JOC3i69>. 

Mataka s synthetic approach to stacked arene-fused bicyclo[4.4.1]undecanes is illustrated for the benzo-fused compound in Fig. 34a [148]. Briefly, dimethyl 1,3-acetonedicarboxylate is alkylated with two equivalents of a 1,2-bis(bromomethyl) arene (l,2-bis(bromomethyl)benzene in this case) to form the bicycloundecane core. Saponification followed by thermal decarboxylation removes the ester groups. Finally, ketalization affords the stacked compound. Variation of thebis(bromomethyl) arene, and stepwise alkylation with two different bis(bromomethyl)arenes, as shown in Fig. 34b, allows for the synthesis of a series of symmetric and unsymmetric compounds, as illustrated by the examples shown in Fig. 34c. 

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