Entry to the bicyclo[4,2,1]nonane system

Synthesis of Bridged Bicyclic Molecules using Halocarbenes. Derivatives of bicyclo[4.2.1]nonane

“…Moreover, it was not clear from our earlier experiment [4], what course constrained cycloheptenyl halides would take, as it was thought that the terms quasi-axial or equatorial would not have the same meaning for the seven membered ring. In fact, reduction of exo-2,3-dichlorobicyclo[4.2.l]non-3-ene (10) gave solely the product of rearrangement, 3-chloro-bicyclo[4.2.l]non-2-ene (15), corroborating the mechanism previously proposed.…”

“…We have briefly reported that the addition of dihalocarbene to bicyclo[3.2.l]oct-2-e m (1) proceeds in high yield [4] ; but that rearrangement of the adduct 2 to its allylic Schcnze I 1 2 X = C I , B r 3 X=CI,Br 4 analogue 3 is difficult to control. Nevertheless, reduction and hydrolysis of 3 affords bicyclo~4.…”