Bicyclo with bridgehead function

When both bridgehead carbon atoms in the bicyclo[4.1.0]heptane system 23 were furnished with carboxylate functions, the central bond was cleaved to produce a seven-membered ring. ... 

Bridgehead functionalization. C1O3 added in small portions with cooling below 35° during 1 hr. to a soln. of bicyclo[3.3.1]nonane in acetic acid-acetic anhydride, and stirred 6 hrs. at room temp. l-bicyclo[3.3.1]nonanol. Y 40-50%. F. e. s. R. C. Bingham and P. v. R. Schleyer, J. Org. Chem. 36, 1198 (1971). 

The shift of the bridgehead carbon in bicyclo[ 1.1.0] butane changes from —4.0 ppm to —14.7 in 250, with = 10.3 Hz (quintet). Signal multiplicity is a function of substrate aggregation which is not germane to this review. 

The synthesis of bicyclo[3.2.l]octa-2,6-diene derivatives with functionality at a bridgehead position is achieved by the reaction pathway 134 -> 135 - 136 - 137888. 

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