Organic Letters,
Год журнала:
2022,
Номер
24(2), С. 637 - 641
Опубликована: Янв. 3, 2022
A
Ni-mediated
decarboxylative
silylation
of
alkynyl
cyclic
carbonates
used
as
versatile
propargylic
surrogates
is
reported
affording
a
wide
range
highly
substituted
2,3-
and
3,4-allenol
products
in
good
yields.
The
formal
cross-coupling
between
tentative
intermediate
Ni(allenyl)
the
silyl
reagent
was
further
extended
to
enantiospecific
conversions
providing
access
chiral
allene
synthons.
This
protocol
marks
first
Ni-catalyzed
proceeding
through
an
SN2'
manifold.
Organic Letters,
Год журнала:
2022,
Номер
24(22), С. 3976 - 3981
Опубликована: Май 27, 2022
Herein,
we
described
an
unprecedented
process
for
generating
allenyl
radicals
through
radical
addition
to
alkynyl
diazo
compounds
followed
by
a
1,2-radical
shift
with
the
loss
of
nitrogen.
Using
this
protocol,
1,3-difunctionalization
synthesis
tetrasubstituted
allenes
RSO2X
(X
=
SeR',
SR',
and
I)
as
sources
was
developed.
The
reactions
were
promoted
visible
light
without
photocatalyst
any
additives.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(36), С. 20031 - 20040
Опубликована: Авг. 29, 2023
Albeit
notable
endeavors
in
enantioselective
carbene
insertion
into
X–H
bonds
(X
=
C,
O,
N,
S,
Si,
B),
the
catalytic
asymmetric
P–H
reactions
still
stand
for
a
long-lasting
challenge.
By
merging
transition-metal
catalysis
with
organocatalysis,
we
achieve
scalable
transformation
between
diazo
pyrazoleamides
and
H-phosphine
oxides
that
upon
subsequent
reduction
delivers
wide
variety
of
optically
active
β-hydroxyl
phosphine
good
yields
high
enantioselectivity.
The
achiral
copper
catalyst
fosters
carbenoid
bond,
while
chiral
cinchona
alkaloid-derived
organocatalyst
controls
outcome.
Density
functional
theory
(DFT)
calculations
further
reveal
chelates
to
organocatalyst,
enhances
its
acidity,
accordingly
promotes
proton
transfer.
Our
work
showcases
potential
combining
organocatalysis
realize
elusive
reactions.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(16)
Опубликована: Фев. 13, 2024
Abstract
We
report
a
highly
enantioselective
intermolecular
C−H
bond
silylation
catalyzed
by
phosphoramidite‐ligated
iridium
catalyst.
Under
reagent‐controlled
protocols,
propargylsilanes
resulting
from
C(sp
3
)−H
functionalization,
as
well
the
regioisomeric
and
synthetically
versatile
allenylsilanes,
could
be
obtained
with
excellent
levels
of
enantioselectivity
good
to
control
propargyl/allenyl
selectivity.
In
case
unsymmetrical
dialkyl
acetylenes,
selectivity
for
functionalization
at
less‐hindered
site
was
also
observed.
A
variety
electrophilic
silyl
sources
(R
SiOTf
R
SiNTf
2
),
either
commercial
or
in
situ
‐
generated,
were
used
reagents,
broad
range
simple
functionalized
alkynes,
including
aryl
alkyl
1,3‐enynes,
drug
derivatives
successfully
employed
substrates.
Detailed
mechanistic
experiments
DFT
calculations
suggest
that
an
η
‐propargyl/allenyl
Ir
intermediate
is
generated
upon
π‐complexation‐assisted
deprotonation
undergoes
outer‐sphere
attack
silylating
reagent
give
propargylic
silanes,
latter
step
identified
enantiodetermining
step.
Chemistry - A European Journal,
Год журнала:
2022,
Номер
28(27)
Опубликована: Март 14, 2022
We
report
herein
a
highly
efficient
palladium-catalyzed
carbene
insertion
into
strained
Si-C
bonds
of
benzosilacyclobutanes,
which
provides
an
method
to
access
α-chiral
silanes.
With
sterically
hindered
ligand,
the
C(sp3
)-Si
bond
benzosilacyclobutanes
occurred
in
excellent
site-
and
enantioselectivity,
while
C(sp2
selectively
with
less
ligands.
Reaction
mechanism,
particular
roles
chiral
ligands
controlling
site-selectivity
reactions,
are
elucidated
by
using
hybrid
density
functional
theory.
Organic Letters,
Год журнала:
2022,
Номер
24(2), С. 637 - 641
Опубликована: Янв. 3, 2022
A
Ni-mediated
decarboxylative
silylation
of
alkynyl
cyclic
carbonates
used
as
versatile
propargylic
surrogates
is
reported
affording
a
wide
range
highly
substituted
2,3-
and
3,4-allenol
products
in
good
yields.
The
formal
cross-coupling
between
tentative
intermediate
Ni(allenyl)
the
silyl
reagent
was
further
extended
to
enantiospecific
conversions
providing
access
chiral
allene
synthons.
This
protocol
marks
first
Ni-catalyzed
proceeding
through
an
SN2'
manifold.
