Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(47)
Опубликована: Окт. 3, 2023
Abstract
Palladium
hydrides
are
traditionally
employed
in
hydrofunctionalization
(i.e.
monofunctionalization)
of
conjugated
dienes
and
enynes,
owning
to
its
facile
protic
hydropalladation
electron‐rich
(or
neutral)
unsaturated
bonds.
Herein,
we
report
a
mild
PdH‐catalyzed
difunctionalization
enynes.
This
protocol
is
enabled
by
the
chemoselectivity
switch
initial
step
achieved
visible
light
enhancement
hydricity
PdH
species.
method
allows
for
cascade
annulation
enynes
with
various
easily
available
abundant
substrates,
such
as
acrylic
acids,
amides,
Baylis–Hillman
adducts,
toward
wide
range
alkenyl
or
alkynyl
lactones,
lactams,
tetrahydrofurans.
also
provides
an
easy
access
complex
spiro‐fused
tricyclic
frameworks.
Communications Chemistry,
Год журнала:
2023,
Номер
6(1)
Опубликована: Янв. 12, 2023
Abstract
Bicyclobutanes
are
among
the
most
highly
strained
isolable
organic
compounds
and
their
associated
low
activation
barriers
to
reactivity
make
them
intriguing
building-blocks
in
chemistry.
In
recent
years,
numerous
creative
synthetic
strategies
exploiting
heightened
have
been
presented
these
discoveries
often
gone
hand-in-hand
with
development
of
more
practical
routes
for
synthesis.
Their
proclivity
as
strain-release
reagents
through
weak
central
C–C
bond
has
harnessed
a
variety
addition,
rearrangement
insertion
reactions,
providing
rapid
access
rich
tapestry
complex
molecular
scaffolds.
This
review
will
provide
an
overview
different
options
available
bicyclobutane
synthesis,
main
classes
that
can
be
prepared
from
bicyclobutanes,
modes
used.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(38), С. 20716 - 20732
Опубликована: Сен. 15, 2023
The
concept
of
strain
in
organic
compounds
is
as
old
modern
chemistry
and
was
initially
introduced
to
justify
the
synthetic
setbacks
along
synthesis
small
ring
systems
(pars
construens
strain).
In
last
decades,
chemists
have
developed
an
arsenal
strain-release
reactions
destruens
strain)
which
can
generate─with
significant
driving
force─rigid
aliphatic
that
act
three-dimensional
alternatives
(hetero)arenes.
Photocatalysis
added
additional
dimension
processes
by
leveraging
energy
photons
create
chemical
complexity
under
mild
conditions.
This
perspective
presents
latest
advancements
photocatalysis─with
emphases
on
mechanisms,
catalytic
cycles,
current
limitations─the
unique
architectures
be
produced,
possible
future
directions.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(22), С. 12324 - 12332
Опубликована: Май 26, 2023
Dearomative
photocycloadditions
are
valuable
chemical
transformations,
serving
as
an
efficient
platform
to
create
three-dimensional
molecular
complexity.
However,
the
photolability
of
original
addition
product
especially
within
context
ortho
cycloadditions
often
causes
undesired
consecutive
rearrangements,
rendering
these
cycloadducts
elusive.
Herein,
we
report
ortho-selective
intermolecular
photocycloaddition
bicyclic
aza-arenes
including
(iso)quinolines,
quinazolines,
and
quinoxalines
by
utilizing
a
strain-release
approach.
With
bicyclo[1.1.0]butanes
coupling
partners,
this
dearomative
[2π
+
2σ]
cycloaddition
enables
straightforward
construction
C(sp3)-rich
bicyclo[2.1.1]hexanes
directly
connected
N-heteroarenes.
Photophysical
experiments
DFT
calculations
revealed
origin
selectivity
indicate
that,
in
originally
proposed
energy
transfer
or
direct
excitation
pathways,
chain
reaction
mechanism
is
operative
depending
on
conditions.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(48)
Опубликована: Авг. 16, 2023
Abstract
Herein,
we
develop
a
new
approach
to
directly
access
architecturally
complex
polycyclic
indolines
from
readily
available
indoles
and
bicyclo[1.1.0]butanes
(BCBs)
through
formal
cycloaddition
promoted
by
commercially
Lewis
acids.
The
reaction
proceeded
stepwise
pathway
involving
nucleophilic
addition
of
BCBs
followed
an
intramolecular
Mannich
form
rigid
indoline‐fused
structures,
which
resemble
indole
alkaloids.
This
tolerated
wide
range
BCBs,
thereby
allowing
the
one‐step
construction
various
indoline
polycycles
containing
up
four
contiguous
quaternary
carbon
centers.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(48)
Опубликована: Окт. 12, 2023
Bicyclo[2.1.1]hexanes
(BCHs)
are
becoming
ever
more
important
in
drug
design
and
development
as
bridged
scaffolds
that
provide
underexplored
chemical
space,
but
difficult
to
access.
Here
a
silver-catalyzed
dearomative
[2π+2σ]
cycloaddition
strategy
for
the
synthesis
of
indoline
fused
BCHs
from
N-unprotected
indoles
bicyclobutane
precursors
is
described.
The
strain-release
operates
under
mild
conditions,
tolerating
wide
range
functional
groups.
It
capable
forming
with
up
four
contiguous
quaternary
carbon
centers,
achieving
yields
99
%.
In
addition,
scale-up
experiment
synthetic
transformations
cycloadducts
further
highlighted
utility.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
63(9)
Опубликована: Ноя. 14, 2023
Visible
light-induced
Pd
catalysis
has
emerged
as
a
promising
subfield
of
photocatalysis.
The
hybrid
nature
radical
species
enabled
wide
array
radical-based
transformations
otherwise
challenging
or
unknown
via
conventional
chemistry.
In
parallel
to
the
ongoing
pursuit
alternative,
readily
available
precursors,
notable
discoveries
have
demonstrated
that
photoexcitation
can
alter
not
only
oxidative
addition
but
also
other
elementary
steps.
This
Minireview
highlights
recent
progress
in
this
area.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(13)
Опубликована: Янв. 30, 2024
Abstract
Herein,
we
have
synthesized
multifunctionalized
2‐oxa‐3‐azabicyclo[3.1.1]heptanes,
which
are
considered
potential
bioisosteres
for
meta
‐substituted
arenes,
through
Eu(OTf)
3
‐catalyzed
formal
dipolar
[4π+2σ]
cycloaddition
of
bicyclo[1.1.0]butanes
with
nitrones.
This
methodology
represents
the
initial
instance
fabricating
bicyclo[3.1.1]heptanes
adorned
multiple
heteroatoms.
The
protocol
exhibits
both
mild
reaction
conditions
and
a
good
tolerance
various
functional
groups.
Computational
density
theory
calculations
support
that
mechanism
likely
involves
nucleophilic
addition
nitrones
to
bicyclo[1.1.0]butanes,
succeeded
by
an
intramolecular
cyclization.
synthetic
utility
this
novel
has
been
demonstrated
in
concise
synthesis
analogue
Rupatadine.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(29), С. 19621 - 19628
Опубликована: Май 13, 2024
For
nearly
60
years,
significant
research
efforts
have
been
focused
on
developing
strategies
for
the
cycloaddition
of
bicyclobutanes
(BCBs).
However,
higher-order
and
catalytic
asymmetric
BCBs
long-standing
formidable
challenges.
Here,
we
report
Pd-catalyzed
ligand-controlled,
tunable
cycloadditions
divergent
synthesis
bridged
bicyclic
frameworks.
The
dppb
ligand
facilitates
formal
(5+3)
vinyl
oxiranes,
yielding
valuable
eight-membered
ethers
with
scaffolds
in
100%
regioselectivity.
Cy-DPEphos
promotes
selective
hetero-[2σ+2σ]
to
access
pharmacologically
important
2-oxabicyclo[3.1.1]heptane
(O-BCHeps).
Furthermore,
corresponding
O-BCHeps
94–99%
ee
has
achieved
using
chiral
(S)-DTBM-Segphos,
representing
first
cross-dimerization
two
strained
rings.
obtained
are
promising
bioisosteres
ortho-substituted
benzenes.
Tetrahedron Chem,
Год журнала:
2024,
Номер
9, С. 100070 - 100070
Опубликована: Фев. 28, 2024
Bicyclo[1.1.0]butanes
(BCBs)
and
[1.1.1]propellanes
(tricyclo[1.1.1.01,3]pentanes,
TCPs)
are
structurally
unique
compounds
with
different
chemical
properties.
Strain-release
driven
reactions
have
emerged
as
an
atom-
step-economic
strategy
for
the
organic
synthesis.
Using
this
strategy,
a
variety
of
functional
ring
molecules
been
efficiently
synthesized,
including
various
cyclobutane
molecules,
bicyclo[2.1.1]hexanes,
bicyclo[1.1.1]pentanes,
others.
More
specifically,
these
strain
release-driven
include
aspects
nucleophilic
addition,
radical
electrophilic
or
transition
metal
catalysis.
This
review
will
discuss
recent
developments
in
strain-release
transformations
bicyclo[1.1.0]butanes
[1.1.1]propellanes.