- A
halonium ion is any
onium ion
containing a
halogen atom
carrying a
positive charge. This
cation has the
general structure R−+X−R′
where X is any halogen...
-
stabilize the
carbocation by
donating electrons at the
expense of the
halonium ion.
Halonium ions can be
identified by
means of NMR spectroscopy. In 1967 the...
-
undergo reductive elimination. In the case of
halonium ions this
involves reduction from a
trivalent halonium to a
monovalent halide coupled with the release...
- to the
heavier halogens,
which have long been
known to form open-chain
halonium ions (such as [Me2Cl]+[Al(OTeF5)4]–) as well as
cyclic haliranium ions...
- from the
nucleophilic abstraction reaction. An
iminium ion
reacts with a
halonium ion
formed in situ by
reaction of an
alkene with iodine.
Lactams form by...
- In chemistry, an
onium ion is a
cation formally obtained by the
protonation of
mononuclear parent hydride of a
pnictogen (group 15 of the
periodic table)...
-
cyclohexene derivatives.
Cyclohexene derivatives, such as imines, epoxides, and
halonium ions,
react with
nucleophiles in a
stereoselective fashion,
affording trans-diaxial...
- + 2 H2O The
addition of
halogens to
alkenes proceeds via
intermediate halonium ions. In
special cases, such
intermediates have been isolated. Bromination...
- dinitrogen.
Stable carbenes also have a
ylidic resonance contributor, e.g.:
Halonium ylides can be
prepared from
allyl halides and
metal carbenoids.
After a...
-
electrophilic addition to the
alkene group with
electrophiles such as
halonium ions, Brønsted
acids and
Lewis acids. In type 3 the
substrates are epoxides...
