Angewandte Chemie,
Journal Year:
2024,
Volume and Issue:
136(25)
Published: April 11, 2024
Abstract
While
polyborylated
alkenes
are
being
recognized
for
their
elevated
status
as
highly
valuable
reagents
in
modern
organic
synthesis,
allowing
efficient
access
to
a
diverse
array
of
transformations,
including
the
formation
C−C
and
C‐heteroatom
bonds,
potential
energy‐transfer
reactive
groups
has
remained
unexplored.
Yet,
this
holds
key
generating
elusive
biradical
species,
which
can
be
captured
by
olefins,
thereby
leading
construction
new
highly‐borylated
scaffolds.
Herein,
we
report
designed
strategy
photosensitized
[2+2]‐cycloadditions
poly‐borylated
with
various
olefins
enabling
regioselective
synthesis
cyclobutane
motifs,
1,1‐di‐,
1,1,2‐tri‐,
1,1,2,2‐tetra‐borylated
cyclobutanes.
In
fact,
these
compounds
belong
family
that
presently
lacks
synthetic
pathways.
Interestingly,
when
α‐methylstyrene
was
used,
reaction
involves
an
interesting
1,5‐hydrogen
atom
transfer
(HAT).
Mechanistic
deuterium‐labeling
studies
have
provided
insight
into
outcome
process.
addition,
cyclobutanes
then
demonstrated
useful
selective
oxidation
processes
resulting
cyclobutanones
γ‐lactones.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(22), P. 15420 - 15427
Published: May 20, 2024
We
report
the
strain-induced
[2
+
2]
cycloadditions
of
cyclic
allenes
for
assembly
highly
substituted
cyclobutanes.
By
judicious
choice
trapping
agent,
complex
scaffolds
bearing
heteroatoms,
fused
rings,
contiguous
stereocenters,
spirocycles,
and
quaternary
centers
are
ultimately
accessible.
Moreover,
we
show
that
resulting
cycloadducts
can
undergo
thermal
isomerization.
This
study
provides
an
alternative
strategy
to
photochemical
accessing
functionalized
cyclobutanes,
while
validating
use
underexplored
strained
intermediates
architectures.
Natural Products and Bioprospecting,
Journal Year:
2024,
Volume and Issue:
14(1)
Published: June 11, 2024
Abstract
Cyclobutanes
are
distributed
widely
in
a
large
class
of
natural
products
featuring
diverse
pharmaceutical
activities
and
intricate
structural
frameworks.
The
[2
+
2]
cycloaddition
is
unequivocally
the
primary
most
commonly
used
method
for
synthesizing
cyclobutanes.
In
this
review,
we
have
summarized
application
with
different
reaction
mechanisms
chemical
synthesis
selected
cyclobutane-containing
over
past
decade.
Graphical
Chemistry - A European Journal,
Journal Year:
2023,
Volume and Issue:
29(54)
Published: July 3, 2023
Abstract
A
photochemical
[2+2]
cycloaddition
of
alkynyl
boronates
and
maleimides
is
reported.
The
developed
protocol
provided
35–70
%
yield
maleimide‐derived
cyclobutenyl
demonstrated
wide
compatibility
with
various
functional
groups.
synthetic
utility
the
prepared
building
blocks
was
for
a
range
transformations,
including
Suzuki
cross‐coupling,
catalytic
or
metal‐hydride
reduction,
oxidation,
reactions.
With
aryl‐substituted
boronates,
products
double
were
obtained
predominantly.
Using
protocol,
cyclobutene‐derived
analogue
Thalidomide
in
one
step.
Mechanistic
studies
supported
participation
triplet‐excited
state
ground
key
step
process.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(46), P. 25061 - 25067
Published: Nov. 8, 2023
A
strategy
to
achieve
photosensitized
[2
+
2]
cycloadditions
by
means
of
temporary
ring
constraint
is
reported.
Specifically,
a
dioxaborole
prepared
that
undergoes
with
wide
variety
alkenes.
This
overcomes
some
challenges
the
cycloaddition
acyclic
substrates.
The
products
can
be
easily
transformed
into
cyclobutyl
diols
or
1,4-dicarbonyl
compounds;
latter
represents
formal
alkene
vicinal
diacylation.
synthetic
utility
this
method
shown
in
synthesis
valuable
heterocycles
and
biatriosporin
D.
Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(9), P. 1403 - 1408
Published: Feb. 27, 2023
The
area
of
energy
transfer
photocatalysis
to
generate
four-membered
rings
is
experiencing
an
unprecedented
level
activity.
Here,
we
report
operationally
simple
method
toward
azetidines
from
2-isoxasoline-3-carboxylates
and
alkenes,
using
[Au(cbz)(NHC)]
complexes
as
photocatalysts.
procedure
enables
the
reaction
for
a
wide
range
substrates.
Mechanistic
studies
confirm
pathway.
This
contribution
adds
earlier
reported
use
these
gold
catalysts
potentially
versatile
tool
in
chemistry
catalysis.
Beilstein Journal of Organic Chemistry,
Journal Year:
2025,
Volume and Issue:
21, P. 854 - 863
Published: April 30, 2025
The
photoactivation
of
organic
molecules
via
energy
transfer
(EnT)
catalysis
is
often
limited
to
conjugated
systems
that
have
low-energy
triplet
excited
states,
with
simple
alkenes
remaining
an
intractable
challenge.
ability
address
this
limitation,
using
high
sensitizers,
would
represent
attractive
platform
for
future
reaction
design.
Here,
we
disclose
the
alkenylboronic
esters
established
alkene
scrambling
as
a
rapid
probe
identify
suitable
catalyst
and
boron
motif.
Cyclic
voltammetry,
UV–vis
analysis,
control
reactions
support
sensitization,
enabling
intramolecular
[2
+
2]
cycloaddition
be
realized
accessing
3D
bicyclic
fragments
containing
handle.
Chemical Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
A
photoredox
nucleophilic
radical
strain-release/[3,3]-rearrangement
cascade
has
been
established
for
the
synthesis
of
polysubstituted
cyclobutanes
by
using
bicyclo[1.1.0]butanes/cyclobutenes
as
acceptors
and
α-silylamines
donors.
The Journal of Organic Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: June 3, 2025
We
report
an
intermolecular,
cross-selective
[2
+
2]
cycloaddition
between
cyclic
styrenes
and
olefin
acceptors
proceeding
via
visible-light
irradiation,
enabled
by
the
extended
triplet
lifetime
of
styrenes.
A
broad
range
olefins,
including
electron-deficient
simple
alkenes,
(hetero)styrenes,
arylimines,
vinyl
boronate
esters,
among
others,
underwent
efficient
with
constrained
four-,
five-,
rigidified
six-membered
rings,
providing
rapid
access
to
sp3-rich
fused
cyclobutane
scaffolds.
Notably,
two
electronically
similar
styrenes,
which
typically
gives
statistical
mixtures
homo-
heterodimers,
proceeded
excellent
chemoselectivity
yield
acyclic
without
requiring
a
large
excess
one
reactant,
facilitated
significant
difference
in
reacting
partners.
Mechanistic
studies
DFT
calculations
support
Dexter
energy
transfer
mechanism
substrate
activation
underscore
critical
role
extension
enabling
observed
reactivity.
The
utility
this
method
is
demonstrated
total
synthesis
lindleyanin,
only
steps.
Chemical Science,
Journal Year:
2022,
Volume and Issue:
14(4), P. 963 - 969
Published: Dec. 21, 2022
There
is
an
increasing
interest
in
cyclobutanes
within
the
medicinal
chemistry
community.
Therefore,
methods
to
prepare
that
contain
synthetic
handles
for
further
elaboration
are
of
interest.
Herein,
we
report
a
new
approach
synthesis
3-borylated
cyclobutanols
via
formal
[3
+
1]-cycloaddition
using
readily
accessible
1,1-diborylalkanes
and
epihalohydrins
or
epoxy
alcohol
derivatives.
1-Substituted
epibromohydrin
starting
materials
provide
access
borylated
containing
substituents
at
three
four
positions
on
cyclobutane
core,
enantioenriched
epibromohydrins
lead
with
high
levels
enantiospecificity
(>98%).
Finally,
derivatization
studies
demonstrate
utility
both
OH
Bpin
handles.