- In
organic chemistry,
antarafacial (Woodward-Hoffmann
symbol a) and
suprafacial (s) are two
topological concepts in
organic chemistry describing the relationship...
- of
antarafacial components usually means zero or one
antarafacial components, respectively, as
transition states involving two or more
antarafacial components...
-
Photoirradiation would require an
antarafacial shift of hydrogen.
Although rare,
there are
examples where antarafacial shifts are favored: In
contrast to...
- (syn/syn stereochemistry) in most cases. Very few
examples of
antarafacial-
antarafacial (anti/anti stereochemistry)
reactions have also been reported...
-
pairs will
proceed through a Hückel
transition state (even
number of
antarafacial components in Woodward–Hoffmann terminology),
while a
pericyclic reaction...
-
suprafacially and none
moving antarafacially,
implying this
reaction is
allowed by the Woodward–Hoffmann rules. For an
antarafacial shift, the
reaction is not...
-
independent of UV light, the pre-cholecalciferol then
undergoes a [1,7]
antarafacial sigmatropic rearrangement and
therein finally isomerizes to form vitamin...
- previtamin D3
spontaneously isomerizes to vitamin D3 (cholecalciferol) in an
antarafacial sigmatropic [1,7]
hydride shift. At room temperature, the transformation...
- isomerisation, a 1,3-sigmatropic reaction, is
unfavorable because an
antarafacial mode is enforced.
Other dimer radical reaction products are
formed as...
-
activation energy and is
characterized by C2 symmetry, a
conrotatory and
antarafacial ring
opening and 8-membered ring aromaticity.
Another interesting system...
