posted on 2016-09-14, 00:00authored byHossay Abas, Christopher
S. Frampton, Alan C. Spivey
Thermal Diels–Alder reactions
of α-amido acrylates
with N-Cbz-1,2-dihydropyridine and cyclopentadiene
have been explored to investigate the factors influencing the endo/exo selectivity. For the dihydropyridine, steric factors
allowed the diastereoselectivity to be modulated to favor either endo- or exo-ester adducts. For cyclopentadiene,
the endo-ester adducts were favored regardless of
steric perturbation, although catalysis by bulky Lewis acids increased
the proportion of exo-ester adducts in some cases.
These Lewis acids were incompatible with the dihydropyridine diene
as they induced its decomposition.