Herein, we report a versatile approach
for the endocyclic ring
opening of bicyclic vinylcyclopropanes triggered by Heck arylations.
The key step for this transformation is a β-C-elimination allowing
the ring expansion of cyclopropanated pyrroles, piperidines, furans,
as well as cyclopentadienes to grant access to the corresponding 1,2-dihydropyridines,
2H-pyrans, 2,3-dihydro-1H-azepines,
and 1,4-cyclohexadienes, respectively. Additionally, gem-disubstituted cyclopropanated furans showed unexpected behavior
by giving diastereoselectively asymmetrically substituted dienes.
Mechanistic studies and theoretical calculations point toward a facile
β-C-elimination with a concomitant shift of Pd along the cyclopropane
moiety, which can successfully compete with the usual termination
step of a Heck reaction via a syn-β-hydride elimination.