Synlett,
Год журнала:
2023,
Номер
34(18), С. 2200 - 2204
Опубликована: Апрель 12, 2023
Abstract
A
convenient
enantiocontrolled
synthesis
of
allenes
(R1R2C=C=CHR3,
R1
=
aryl/alkyl,
R2,
R3
alkyl)
is
described
based
on
carbenoid
eliminative
cross-coupling
(CEXC)
between
geometrically
pure
higher-order
α-(methylthio)vinylcuprates,
generated
in
situ
by
carbocupration
thioalkynes
(then
activation
addition
n-BuLi),
and
enantioenriched
α-(carbamoyloxy)alkylboronates
(15
examples,
30–78%
yield,
15–95%
ee).
The
stereochemical
fidelity
this
CEXC
process
substrate
dependent,
a
phenomenon
tentatively
attributed
to
putative
organocopper-mediated
allene
racemization
pathway.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(13), С. 9241 - 9251
Опубликована: Март 19, 2024
Much
attention
has
been
focused
on
the
catalytic
asymmetric
creation
of
single
chiral
centers
or
two
adjacent
stereocenters.
However,
construction
nonadjacent
stereocenters
is
significant
importance
but
challenging
because
lack
remote
induction
models.
Herein,
based
a
C═C
bond
relay
strategy,
we
report
synergistic
Pd/Cu-catalyzed
1,5-double
model.
All
four
stereoisomers
target
products
bearing
1,5-nonadjacent
involving
both
allenyl
axial
and
central
chirality
could
be
obtained
divergently
by
simply
changing
combination
catalysts
with
different
configurations.
Control
experiments
DFT
calculations
reveal
novel
mechanism
1,5-oxidative
addition,
contra-thermodynamic
η3-allyl
palladium
shift,
conjugate
nucleophilic
substitution,
which
play
crucial
roles
in
control
reactivity,
regio-,
enantio-,
diastereoselectivity.
It
expected
that
this
strategy
may
provide
general
protocol
for
synthesis
structural
motifs
distant
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(22)
Опубликована: Март 23, 2024
Abstract
Despite
the
significance
of
chiral
allene
skeletons
in
catalysis,
organic
synthesis
and
medicinal
chemistry
et
al.,
there
is
a
scarcity
reports
on
axially
allenyl
phosphorus
compounds.
Here,
we
disclosed
an
efficient
straightforward
cascade
reaction
between
ethynyl
ketones
phosphine
oxides,
resulting
broad
array
trisubstituted
allenes
incorporating
moiety
high
yields
with
excellent
stereoselectivities
facilitated
by
peptide‐mimic
phosphonium
salt
(PPS)
Additionally,
comprehensive
series
mechanistic
experiments
have
been
conducted
to
elucidate
that
this
proceeds
via
asymmetric
Pudovik
addition
followed
subsequent
phospha
‐Brook
rearrangement
occurs
concomitantly
kinetic
resolution,
representing
stereospecific
protonation
process
facilitating
central‐to‐axial
chirality
transfer
manner.
We
anticipate
our
research
will
pave
way
for
promising
exploration
novel
stereo‐induction
pattern
addition/
reaction.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 18, 2024
A
Pd-catalyzed
asymmetric
higher-order
dipolar
cycloaddition
between
allenyl
carbonates
and
azadienes
is
achieved
by
exploiting
novel
alkylidene-π-allyl-Pd
dipoles.
This
research
provides
a
modular
platform
for
the
synthesis
of
challenging
chiral
endocyclic
allenes
bearing
medium-sized
heterocyclic
motif
centrally
stereocenter
in
good
yields
with
high
enantio-
diastereoselectivities
(29
examples,
up
to
97%
yield,
97:3
er
>19:1
dr).
Experimental
computational
studies
elucidate
possible
reaction
mechanism
observed
stereochemical
results.
Based
on
mechanistic
understanding,
new
π-propargyl-Pd
dipole
was
designed
further
extend
success
higher
order
strategy
10-membered
alkynes
from
propargyl
(13
98%
yield
94.5:5.5
er).
Organic Chemistry Frontiers,
Год журнала:
2024,
Номер
11(6), С. 1843 - 1857
Опубликована: Янв. 1, 2024
This
work
summarizes
recent
progress
in
nickel-catalyzed
propargylic
substitution
reactions,
categorizing
them
based
on
the
diverse
types
of
nucleophiles
involved,
with
a
specific
focus
exploring
asymmetric
transformations.
Nature Communications,
Год журнала:
2023,
Номер
14(1)
Опубликована: Авг. 10, 2023
Catalytic
enantioselective
introduction
of
a
propargyl
group
constitutes
one
the
most
important
carbon-carbon
forming
reactions,
as
it
is
versatile
to
be
transformed
into
diverse
functional
groups
and
frequently
used
in
synthesis
natural
products
biologically
active
molecules.
Stereoconvergent
transformations
racemic
precursors
single
enantiomer
via
radicals
represent
powerful
strategy
provide
new
reactivity.
However,
only
few
Cu-
or
Ni-catalyzed
protocols
have
been
developed
with
limited
reaction
modes.
Herein,
photoredox/cobalt-catalyzed
regio-,
diastereo-
addition
aldehydes
presented,
enabling
construction
broad
scope
homopropargyl
alcohols
that
are
otherwise
difficult
access
high
efficiency
stereoselectivity
from
carbonates.
Mechanistic
studies
DFT
calculations
provided
evidence
for
involvement
radicals,
origin
stereoconvergent
process
stereochemical
models.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(13), С. 7621 - 7627
Опубликована: Март 27, 2023
Although
the
Heck
reactions
of
alkene
partners
with
various
electrophiles
have
achieved
great
success,
variant
focused
on
carbon═heteroatom
counterparts
still
remains
elusive.
Herein,
we
report
a
Pd(0)-catalyzed
asymmetric
intramolecular
hydrazone-type
reaction
N-[(Z)-3-iodoallyl]-aminoacetaldehyde
and
hydrazine
hydrate
(NH2NH2–H2O),
wherein
required
hydrazone
is
in
situ
generated
via
an
acid-promoted
condensation.
A
key
strategic
advantage
this
paradigm
that
resultant
product
allylic
diazene
rapidly
undergoes
stereospecific
denitrogenative
[1,5]-sigmatropic
rearrangement,
eventually
furnishing
domino
sequence
toward
3-substituted
tetrahydropyridine
(THP)
high
enantioselectivity.
The
substrate-induced
diastereoselective
version
has
also
been
realized,
exclusively
giving
cis-2,5-disubstituted
THPs.
utility
demonstrated
by
formal
synthesis
multiple
valuable
bioactive
targets,
including
3-ethylindoloquinolizine,
preclamol,
niraparib.
JACS Au,
Год журнала:
2023,
Номер
3(10), С. 2862 - 2872
Опубликована: Сен. 25, 2023
Regio-divergent
propargylic
substitution
to
generate
functionally
diverse
products
from
identical
starting
materials
remains
a
formidable
challenge,
probably
due
the
unpredictable
regiochemical
complexity.
In
practically,
synthesis
of
α-quaternary
propargylic-substituted
is
still
much
less
developed,
and
preprepared
nucleophiles
are
generally
applied
in
this
type
reaction
with
substrates,
which
limits
efficiency
diversity
obtained
products.
Herein,
we
disclose
unprecedented
three-component
α-diazo
esters
amines
carbonates
under
dirhodium/palladium
dual
catalysis.
The
key
success
multicomponent
avoid
two-component
side
reactions
through
tandem
process
dirhodium(II)-catalyzed
carbene
insertion
palladium-catalyzed
regiodivergent
substitution.
judicious
selection
diphosphine
(dppf)
or
monophosphine
(tBuBrettphos)
as
ligand
crucial
for
different
switchable
way,
1,3-dienyl
propargylated
products,
high
regio-
chemoselectivities.
