Diastereoselective Indole-Dearomative Cope Rearrangements by Compounding Minor Driving Forces.
Subhadip De,
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Breanna Tomiczek,
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Yinuo Yang
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et al.
Published: Jan. 10, 2022
Reported
herein
is
the
discovery
of
a
diastereoselective
indole-dearomative
Cope
rearrangement.
A
suite
minor
driving
forces
(substrate
destabilizing
effects;
product
stabilizing
effects)
are
what
promote
this
otherwise
unfavorable
dearomatization
reaction.
These
include
following
that
work
in
concert
to
overcome
penalty
for
dearomatization:
(i.)
steric
congestion
starting
material,
(ii.)
alkylidene
malononitrile
and
stilbene
conjugation
events
product,
(iii.)
an
unexpected
intramolecular
p–p*
stack
on
side
equilibrium.
The
key
substrates
rapidly
assembled
from
alkylidenemalononitriles
indole-phenylmethanol
derivatives
resulting
many
successful
examples
(high
yields
diastereoselectivity).
products
structurally
complex
bearing
vicinal
stereocenters
generated
by
dearomative
They
also
contain
variety
functional
groups
interconversion
architectures.
On
line,
described
proof-of-concept
strategies
achieving
enantioselectivity
conversion
valuable
functionalized
small
drug-like
molecules.
Language: Английский
Carbodefluorination via a carbene-initiated rearrangement strategy
Published: March 1, 2022
The
C–F
bond
cleavage
and
C–C
formation
(i.e.,
carbodefluorination)
of
readily
accessible
(per)fluoroalkyl
groups
constitutes
an
atom-economical
efficient
route
to
partially
fluorinated
compounds.
However,
the
selective
mono-carbodefluorination
trifluoromethyl
(CF3)
remains
a
formidable
challenge,
due
notorious
inertness
risk
over-defluorination
arising
from
strength
decrease
as
defluorination
proceeds.
Herein,
we
report
carbene-initiated
rearrangement
strategy
for
carbodefluorination
fluoroalkyl
ketones
with
β,γ-unsaturated
alcohols.
reaction
starts
silver
carbene
ketone
N-triftosylhydrazone,
followed
by
nucleophilic
addition
alcohol
form
key
oxonium
ylide
intermediate,
which
triggers
HF
elimination
through
Claisen
in
situ
generated
difluorovinyl
ether.
This
method
described
here
is
versatile
enables
conversion
into
skeletally
functionally
diverse
α-mono-
α,α-difluoro-γ,δ-unsaturated
ketones.
mechanism
origin
chemoselectivity
were
established
experimental
computational
approaches.
Collectively,
current
integrates
successive
on
single
molecule
entity
intramolecular
cascade
process,
thereby
offering
significant
advances
over
existing
stepwise
strategies
term
selectivity,
efficiency,
functional
group
tolerance,
etc.
Language: Английский
Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species
Published: Nov. 30, 2021
The
selective
reductive
coupling
of
vinyl
arenes
and
ketones
represents
a
versatile
approach
for
the
rapid
construction
enantiomerically
enriched
tertiary
alcohols.
Herein,
we
demonstrate
CuH-catalyzed
regiodivergent
ketones,
in
which
selectivity
is
controlled
by
ancillary
ligand.
This
leverages
an
situ
generated
benzyl-
or
dearomatized
allyl-Cu
intermediate,
yielding
either
exocyclic
addition
products,
respectively.
method
exhibits
excellent
regio-,
diastereo-
enantioselectivity,
tolerates
range
common
functional
groups
heterocycles.
Computational
studies
suggest
that
regio-
enantioselectivity
are
ligand,
while
diastereoselectivity
enforced
steric
interactions
between
alkyl-Cu
intermediate
ketone
substrates
six-membered
cyclic
transition
state.
Language: Английский
Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species
Published: Nov. 19, 2021
The
selective
reductive
coupling
of
vinyl
arenes
and
ketones
represents
a
versatile
approach
for
the
rapid
construction
enantiomerically
enriched
tertiary
alcohols.
Herein,
we
demonstrate
CuH-catalyzed
regiodivergent
ketones,
in
which
selectivity
is
controlled
by
ancillary
ligand.
This
leverages
an
situ
generated
benzyl-
or
dearomatized
allyl-Cu
intermediate,
yielding
either
exocyclic
addition
products,
respectively.
method
exhibits
excellent
regio-,
diastereo-
enantioselectivity,
tolerates
range
common
functional
groups
heterocycles.
Computational
studies
suggest
that
regio-
enantioselectivity
are
ligand,
while
diastereoselectivity
enforced
steric
interactions
between
alkyl-Cu
intermediate
ketone
substrates
six-membered
cyclic
transition
state.
Language: Английский