Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(34), P. 13759 - 13768
Published: Aug. 16, 2021
Herein
we
report
the
copper-catalyzed
silylation
of
propargylic
difluorides
to
generate
axially
chiral,
tetrasubstituted
monofluoroallenes
in
both
good
yields
(27
examples
>80%)
and
enantioselectivities
(82-98%
ee).
Compared
previously
reported
synthetic
routes
chiral
allenes
(ACAs)
from
prochiral
substrates,
a
mechanistically
distinct
reaction
has
been
developed:
enantiodiscrimination
between
enantiotopic
fluorides
set
an
axial
stereocenter.
DFT
calculations
vibrational
circular
dichroism
(VCD)
suggest
that
β-fluoride
elimination
alkenyl
copper
intermediate
likely
proceeds
through
syn-β-fluoride
pathway
rather
than
anti-elimination
pathway.
The
effects
C1-symmetric
Josiphos-derived
ligand
on
reactivity
enantioselectivity
were
investigated.
Not
only
does
this
showcase
species
(like
their
alkyl
counterparts)
can
undergo
elimination,
but
be
achieved
enantioselective
fashion.
Angewandte Chemie International Edition,
Journal Year:
2019,
Volume and Issue:
58(35), P. 11998 - 12003
Published: June 13, 2019
Abstract
The
first
catalytic
method
for
diastereo‐
and
enantioselective
synthesis
of
allylic
boronates
bearing
a
Z
‐trisubstituted
alkenyl
fluoride
is
disclosed.
Boryl
substitution
performed
with
either
‐
or
E
‐allyldifluoride
catalyzed
by
bisphosphine/Cu
complexes,
affording
products
in
up
to
99
%
yield
>98:2
/
selectivity
99:1
enantiomeric
ratio.
A
variety
subsequent
modifications
are
feasible,
notable
examples
diastereoselective
additions
aldehydes/aldimines
access
homoallylic
alcohols/amines
containing
fluorosubstituted
stereogenic
quaternary
center.
ACS Catalysis,
Journal Year:
2018,
Volume and Issue:
9(1), P. 38 - 43
Published: Nov. 19, 2018
Efficient
methods
for
the
synthesis
of
fluoroalkylated
alkenylboronates
are
very
limited,
despite
their
importance
in
modern
organic
synthesis.
Herein,
we
report
a
palladium-catalyzed
trans-fluoroalkylation–borylation
alkynes
with
fluoroalkyl
iodides
and
B2pin2.
The
reaction
tolerates
series
difluoroalkyl
perfluoroalkyl
can
enable
coupling
variety
alkynes,
including
internal
terminal
high
efficiency,
functional
group
compatibility,
regio-
stereoselectivities.
Preliminary
mechanistic
studies
reveal
that
trans-fluoroalkylated
alkenyl
iodide
is
key
intermediate,
which
subsequently
undergoes
borylation
to
produce
alkenylboronate.
Organic Letters,
Journal Year:
2020,
Volume and Issue:
22(4), P. 1542 - 1546
Published: Jan. 28, 2020
In
this
study,
a
facile
and
efficient
method
to
synthesize
monofluoroalkenes
by
photoredox
catalytic
defluorinative
alkylation
of
gem-difluoroalkenes
with
4-alkyl-1,4-dihydropyridines
under
mild
conditions
(room
temperature)
is
described.
This
novel
strategy
applicable
for
broad
range
gem-difluoroalkene
substrates
good
functional
group
tolerance
variety
(including
primary,
secondary,
even
tertiary
alkyl
radicals).
Moreover,
it
also
allows
the
challenging
radical
coupling
glycosyl-based
(DHPs)
monofluoroalkenylated
saccharides.
Chinese Journal of Chemistry,
Journal Year:
2019,
Volume and Issue:
37(10), P. 1009 - 1014
Published: Aug. 14, 2019
Summary
of
main
observation
and
conclusion
Silylated
fluoroalkenes
are
important
synthetic
intermediates
with
complementary
reactivity,
which
play
a
key
role
in
the
construction
natural
products,
pharmaceuticals,
manmade
materials.
Converting
normally
highly
stable
into
silylated
by
selective
defluorosilylation
is
challenging
task.
Herein,
we
report
simple,
inexpensive
robust
variety
silylboronates
presence
alkoxy
base
to
directly
synthesize
various
fluoroalkenes.
The
protocol
features
mild
safe
reaction
conditions
that
avoid
catalyst,
transition
metal,
ligand,
high
temperature
tolerates
wide
scope
fluoroalkene
substrates
without
compromising
efficiency.
Density
functional
theory
calculations
show
transient
silyl
anion
complex
undergoes
an
S
N
2’
or
V
substitution,
responsible
for
this
base‐mediated
defluorosilylation.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(34), P. 13759 - 13768
Published: Aug. 16, 2021
Herein
we
report
the
copper-catalyzed
silylation
of
propargylic
difluorides
to
generate
axially
chiral,
tetrasubstituted
monofluoroallenes
in
both
good
yields
(27
examples
>80%)
and
enantioselectivities
(82-98%
ee).
Compared
previously
reported
synthetic
routes
chiral
allenes
(ACAs)
from
prochiral
substrates,
a
mechanistically
distinct
reaction
has
been
developed:
enantiodiscrimination
between
enantiotopic
fluorides
set
an
axial
stereocenter.
DFT
calculations
vibrational
circular
dichroism
(VCD)
suggest
that
β-fluoride
elimination
alkenyl
copper
intermediate
likely
proceeds
through
syn-β-fluoride
pathway
rather
than
anti-elimination
pathway.
The
effects
C1-symmetric
Josiphos-derived
ligand
on
reactivity
enantioselectivity
were
investigated.
Not
only
does
this
showcase
species
(like
their
alkyl
counterparts)
can
undergo
elimination,
but
be
achieved
enantioselective
fashion.
