REARRANGEMENTS OF TRICYCLIC KETONES - [3.3.3]PROPELLANE FORMATION VIAA GAMMA-ENOLATE REVEALED IN AN APPROACH TO THE PENTALENENE SKELETON THROUGH BETA-ENOLIZATION
Ha. Patel et al., REARRANGEMENTS OF TRICYCLIC KETONES - [3.3.3]PROPELLANE FORMATION VIAA GAMMA-ENOLATE REVEALED IN AN APPROACH TO THE PENTALENENE SKELETON THROUGH BETA-ENOLIZATION, Canadian journal of chemistry, 72(1), 1994, pp. 56-68
The known isomerization of the tricyclo[5.3.1.0(1,5)]- to the [6.3.0.0
(1,5)]undecane skeleton by beta-homoenolization led to examination of
yl-6-methoxymethyltricyclo[5.3.1.0(1,5)]undecanone (6) as a potential
precursor for the synthesis of pentalenene, a naturally occurring sesq
uiterpenoid, utilizing a beta-enolate rearrangement as a key step. Whi
le the anticipated rearrangement of 6 occurs, it is a minor process. T
he major rearrangement product arises by generation of a gamma-enolate
intermediate from a tricyclic enone formed by loss of methanol from 6
. This constitutes a new route to [3.3.3]propellanes and provides a th
ird example of gamma-enolate rearrangement. Structures of the products
were established primarily from their H-1 and (13)Cmr spectra.