Lewis Base-Catalyzed Interhalogenation of Terminal Allenes: Selective Strategy for Accessing Vicinal Vinylic, Allylic Heterodihalides
Alexandra E. Lubaev,
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Favour Eze,
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Manjula D. Rathnayake
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et al.
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 28, 2025
Though
precedent
remains
limited,
the
selective
interhalogenation
of
allenes
offers
a
valuable
synthetic
strategy
to
access
products
where
each
halide
exhibits
orthogonal
reactivity.
Here,
we
describe
Lewis
base-catalyzed
approach
for
dihalogenation
(bromochlorination,
iodochlorination,
iodobromination,
and
dibromination)
terminal
allenes.
By
employing
just
1
mol
%
triphenylphosphine
oxide
or
hexamethylphosphoramide
activate
thionyl
halides
in
presence
electrophilic
halogenation
reagents,
achieve
conversion
monosubstituted
vicinal
allylic,
vinylic
dihalides
with
up
93%
yield
>20:1
regioisomeric
ratio,
favoring
branched
dihalogenated
product.
A
range
functional
groups
is
tolerated,
including
nitrile,
ester,
phosphate,
sulfonamide,
silyl
groups,
reaction
proved
be
scalable.
The
utility
various
dihalide
was
investigated
substitution
cross-coupling
chemistry,
highlighting
distinct
reactivity
among
different
classes.
Language: Английский
Electrochemical Cyclization of 2,3-Allenols
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 3, 2025
An
efficient
electrochemical
bromocyclization
of
allenols
has
been
realized
for
the
synthesis
spirocyclic
2,5-dihydrofurans.
The
reaction
used
commercially
available
and
nontoxic
KBr
as
brominating
source
in
a
simple
setup
under
open-air
conditions.
Notably,
optically
active
products
can
be
obtained
from
2,3-allenols
without
any
racemization,
further
enhancing
synthetic
utility.
Language: Английский