Journal of the American Chemical Society,
Год журнала:
2021,
Номер
143(41), С. 17191 - 17199
Опубликована: Окт. 6, 2021
Radical-induced
1,2-metalate
rearrangements
of
boronate
complexes
are
an
emerging
and
promising
class
reactions
that
allow
multiple
new
bonds
to
be
formed
in
a
single,
tunable
reaction
step.
These
involve
the
addition
alkyl
radical,
typically
generated
from
iodide
under
photochemical
activation,
complex
produce
α-boryl
radical
intermediate.
From
this
there
two
plausible
pathways
can
trigger
product
forming
rearrangement:
iodine
atom
transfer
(IAT)
or
single
electron
(SET).
Previous
steady-state
techniques
have
struggled
differentiate
these
pathways.
Here
we
apply
state-of-the-art
time-resolved
infrared
absorption
spectroscopy
resolve
all
steps
cycle
by
mapping
production
consumption
reactive
intermediates
over
picosecond
millisecond
time
scales.
We
technique
recently
reported
involving
electron-deficient
strained
σ-bond
bicyclo[1.1.0]butyl
form
cyclobutyl
boronic
ester.
show
previously
proposed
SET
mechanism
does
not
adequately
account
for
observed
spectral
kinetic
data.
Instead,
demonstrate
IAT
is
preferred
pathway
likely
operative
other
type.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(25)
Опубликована: Апрель 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.
Organic Letters,
Год журнала:
2022,
Номер
24(4), С. 1100 - 1104
Опубликована: Янв. 26, 2022
Radical
1,3-carboheteroarylation
and
1,3-hydroalkylation
of
allylboronic
esters
comprising
a
1,2-boron
shift
is
reported.
Allylboronic
are
generally
used
in
synthesis
as
allylation
reagents,
where
the
boronic
ester
moiety
gets
lost.
In
introduced
cascades,
alkylboronic
obtained
with
boron
entity
remaining
product.
The
carboheteroarylation
conducted
without
metal
catalyst,
achieved
using
iron
catalysis.
Both
reactions
work
efficiently
under
mild
conditions.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(34)
Опубликована: Июнь 16, 2023
Abstract
Operationally
simple
strategies
to
assemble
boron
containing
organic
frameworks
are
highly
enabling
in
synthesis.
While
conventional
retrosynthetic
logic
has
engendered
many
platforms
focusing
on
the
direct
formation
of
C−B
bonds,
α‐boryl
radicals
have
recently
reemerged
as
versatile
open‐shell
alternatives
access
organoborons
via
adjacent
C−C
bond
formation.
Direct
light‐enabled
α‐activation
is
currently
contingent
photo‐
or
transition
metal‐catalysis
activation
efficiently
generate
radical
species.
Here,
we
disclose
a
facile
α‐halo
boronic
esters
using
only
visible
light
and
Lewis
base
enable
homolytic
scission.
Intermolecular
addition
styrenes
facilitates
rapid
construction
E
‐allylic
esters.
The
simplicity
permits
strategic
merger
this
construct
with
selective
energy
transfer
catalysis
complimentary
stereodivergent
synthesis
Z
Organic & Biomolecular Chemistry,
Год журнала:
2020,
Номер
18(44), С. 8939 - 8974
Опубликована: Янв. 1, 2020
This
review
systematically
outlined
the
research
in
area
of
transition
metal
free
synthesis
alkyl
pinacol
boronates,
which
are
versatile
and
important
scaffolds
to
construct
diverse
organic
compounds.
Angewandte Chemie International Edition,
Год журнала:
2020,
Номер
59(39), С. 17245 - 17249
Опубликована: Июнь 24, 2020
A
general
and
efficient
approach
for
the
preparation
of
1,3-bis-(boryl)alkanes
is
introduced.
It
shown
that
readily
generated
vinylboron
ate
complexes
react
with
commercially
available
ICH
Organic Letters,
Год журнала:
2021,
Номер
23(21), С. 8246 - 8251
Опубликована: Окт. 15, 2021
A
visible-light-triggered
radical
cascade
sulfonylation/aryl
migration/desulfonylation
and
C-S/Se
bond
formation
reaction
of
butenyl
benzothiazole
sulfone
with
thiosulfonates
or
selenosulfonates
is
developed.
This
study
affords
the
1,2,4-trifunctionalization
derivatives
under
mild
conditions.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(30)
Опубликована: Май 20, 2022
Abstract
A
novel
distal
radical
rearrangement
of
alkoxyphosphine
is
developed
for
the
first
time
and
applied
to
regioselective
fluoroalkylphosphorylation
unactivated
olefins.
By
employing
a
one‐pot
two‐step
reaction
(bis)homoallylic
alcohols,
organophosphine
chlorides,
fluoroalkyl
iodides
under
CFL
(compact
fluorescence
light)
irradiation,
series
fluoroalkylphosphorylated
alkyl
alcohols
are
easily
synthesized
by
regiospecific
installing
phosphonyl
onto
inner
carbon
terminal
olefins
further
iodination/hydroxylation.
Mechanism
studies
reveal
that
migration
undergoes
distinctive
cyclization/β‐scission
on
lone
electron
pair
phosphorus,
resulting
in
C−P
bond
formation
C−O
cleavage.
