A silver ion catalyzed [3.1.1]propellane rearrangement. 2,4-Methano-2,4-didehydroadamantane retro-carbene ring opening

Abstract

The propellane (I) undergoes Ag(I)‐induced rearrangement to give the isomeric dimers (II) and (III).

Nature of Bonding in [3.1.1]Propellane. Vibrational Spectra and Normal Coordinate Analysis of 2,4-Methano-2,4-didehydroadamantane, 2,4-(Dimethylmethano)-2,4-didehydroadamantane, and Their Dihydro Congeners

“…7,8 Contrary to the usual carbon-carbon single bond, the central bond in small-ring propellanes, such as in 2,4-methano-2,4-didehydroadamantane (1) and 2,4-(dimethylmethano)-2,4-didehydroadamantane (2) (Figure 1), is highly reactive toward electrophiles and free radicals. [10][11][12][13] The bond in 1 and 2 can easily be reduced by electron-transfer hydrogenation to give 2,4-methanoadamantane (3) and 2,4-(dimethylmethano)adamantane (4), respectively. 11,12 Also, [3.1.1]propellanes 1 and 2 readily add disulfides and carbon tetrachloride across the central bond to give the corresponding 2,4-disubstituted 2,4-methanoadamantanes.…”

“…Contrary to the usual carbon−carbon single bond, the central bond in small-ring propellanes, such as in 2,4-methano-2,4-didehydroadamantane ( 1 ) and 2,4-(dimethylmethano)-2,4-didehydroadamantane ( 2 ) (Figure ), is highly reactive toward electrophiles and free radicals. − The bond in 1 and 2 can easily be reduced by electron-transfer hydrogenation to give 2,4-methanoadamantane ( 3 ) and 2,4-(dimethylmethano)adamantane ( 4 ), respectively. , Also, [3.1.1]propellanes 1 and 2 readily add disulfides and carbon tetrachloride across the central bond to give the corresponding 2,4-disubstituted 2,4-methanoadamantanes . The unusual chemical reactivities of 1 and 2 have been attributed to the electron-density distribution in the central propellane bond. , Whereas chemical evidence indicates that the electron density on the central bond of small propellanes is considerably higher at the back side of the inverted carbon atoms than between them, more substantial support of this hypothesis was needed.…”