Four-membered
heterocycles
are
highly
sought
after
in
modern
drug
discovery
as
they
provide
beneficial
properties
to
the
target
molecules.
Despite
tremendous
efforts
by
synthetic
research
community,
there
is
a
need
for
simple
and
new
method
incorporate
these
motifs
into
design
Herein,
we
reveal
cycloisomerization
strategy
construction
of
oxetane
azetidine
rings
via
metal
hydride
hydrogen
atom
transfer/radical
polar
crossover,
which
challenging
both
enthalpically
entropically.
This
suitable
synthesizing
polysubstituted
four-membered
heterocycles.
mild
functional-group
tolerant
reaction
has
broad
substrate
scope,
including
spiro
structure,
an
important
motif
research.
Various
heterocyclic
building
blocks
can
be
synthesized
product
derivatization.
We
also
discuss
mechanism,
focusing
on
four
membered
ring
formation,
deuterium
experiment
DFT
studies.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(46)
Published: Aug. 6, 2024
Abstract
A
cobalt‐catalyzed
intramolecular
Markovnikov
hydroalkoxycarbonylation
and
hydroaminocarbonylation
of
unactivated
alkenes
has
been
developed,
enabling
highly
chemo‐
regioselective
synthesis
α
‐alkylated
γ
‐lactones
‐lactams
in
good
yields.
The
mild
reaction
conditions
allow
use
mono‐,
di‐
trisubstituted
bearing
a
variety
functional
groups.
Preliminary
mechanistic
studies
suggest
the
proceeds
through
CO‐mediated
hydrogen
atom
transfer
(HAT)
radical‐polar
crossover
(RPC)
process,
which
cationic
acylcobalt(IV)
complex
is
proposed
as
key
intermediate.
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 8, 2025
We
report
intramolecular
photocatalyzed
cycloisomerization
of
unactivated
olefins
with
pendant
nucleophiles.
The
reaction
proceeds
under
mild
conditions
and
utilizes
guanidines,
ureas,
isoureas,
isothioureas,
carbonates
to
yield
several
different
five-,
six-,
seven-membered
heterocycles.
Use
benzothiazinoquinoxaline
as
an
organophotocatalyst
cobalt–salen
catalyst
obviates
the
need
for
a
stoichiometric
oxidant
or
reductant.
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 26, 2025
The
intermolecular
hydroamination
of
unactivated
alkenes
with
simple
amines
continues
to
be
an
attractive
and
challenging
undertaking
in
organic
synthesis.
current
state-of-the-art
strategies
for
photocatalyzed
usually
commence
the
formation
a
C–N
bond,
thereby
delivering
exclusively
anti-Markovnikov
products.
We
herein
reported
facile
mild
Markovnikov
anilines
through
photoredox
cobalt-catalyzed
hydrogen
atom
transfer
followed
by
radical-polar
crossover
nucleophilic
amination
process.
reaction
features
wide
substrate
scope,
good
functional
group
tolerance,
excellent
yields.
Application
this
late-stage
functionalization
relatively
complex
natural
products
bioactive
molecules
further
increases
utility
developed
methodology.
Organic Chemistry Frontiers,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
A
bifunctional
iron-mediated
multicomponent
reaction
for
Markovnikov-selective
hydrothiolation
of
alkenes
has
been
established.
The
involves
an
hydrogen
atom
transfer
and
a
single
electron
process.
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 14, 2025
Herein,
we
report
a
visible-light-driven
and
cobalt-mediated
1,4-hydroamination
reaction
of
1,3-dienes
with
arylmines
as
the
nucleophiles.
The
involves
regioselective
addition
[CoIII]–H
to
1,3-diene,
followed
by
oxidation
nucleophilic
substitution
amines.
Using
Ir(ppy)3
photocatalyst
enables
cobalt
redox
cycle
be
implemented
without
using
an
external
oxidant
hydride
regent.
This
protocol
can
applied
well
forge
carbon–oxygen
carbon–sulfur
bonds
in
analogous
way.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(11), P. 8405 - 8413
Published: May 15, 2024
Construction
of
valuable
vicinal
Si,O-alkanes,
which
exhibit
potential
utility
in
pharmaceuticals
and
materials
science,
has
yet
to
be
restricted
prefunctionalized
reactants.
Plenty
efforts
have
been
made,
using
alkenes
as
nonprefunctionalized
starting
materials.
Despite
that,
methodology
from
easily
accessible
alkynes
rarely
developed,
Si,O-alkanes
containing
Si–H
seldom
explored.
Here,
we
report
one-pot
two-step
cobalt-catalyzed
sequential
hydrosilylation/hydroxylation
terminal
with
commercially
available
TEMPO
diphenylsilane
via
ligand
relay
catalysis,
featuring
low
catalyst
loading
(1
mol
%),
mild
conditions,
broad
substrate
scope.
The
successful
execution
the
double
hydrofunctionalization
protocol
ensures
that
characterized
are
obtained
smoothly
good
yields
regioselectivity.
derivatizations
bond
also
demonstrated,
delivering
silanol,
siloxane,
tetra-substituted
silane.
possible
mechanism
proposed
based
on
control
experiments
computational
studies.
JACS Au,
Journal Year:
2022,
Volume and Issue:
2(5), P. 1071 - 1077
Published: May 6, 2022
The
cycloisomerization
of
β-,
γ-,
and
δ-unsaturated
N-acyl
sulfonamides
to
N-sulfonyl
lactams
imidates
is
reported.
This
transformation
effected
in
the
presence
a
CoIII(salen)
catalyst
using
t-BuOOH
or
air
as
oxidant.
method
shows
good
functional
group
tolerance
(alkyl,
aryl,
heteroaryl,
ether,
N-Boc)
furnishes
an
underexplored
class
cyclic
building
blocks.
strong
solvent
dependence
investigated,
synthetic
versatility
imidate
product
highlighted.
The Journal of Organic Chemistry,
Journal Year:
2023,
Volume and Issue:
88(5), P. 3277 - 3281
Published: Feb. 21, 2023
Described
here
is
a
method
for
intermolecular
hydroalkoxylation
and
hydrocarboxylation
of
2-azadienes
through
cobalt-catalyzed
hydrogen
atom
transfer
oxidation.
This
protocol
provides
source
2-azaallyl
cation
equivalents
under
mild
conditions,
chemoselective
in
the
presence
other
C═C
double
bonds,
requires
no
excess
amount
added
alcohol
or
oxidant.
Mechanistic
studies
suggest
that
selectivity
arises
from
lowering
transition
state
leads
to
highly
stabilized
radical.
Advanced Synthesis & Catalysis,
Journal Year:
2023,
Volume and Issue:
365(14), P. 2356 - 2360
Published: June 30, 2023
Abstract
A
commercially
available
cobalt
complex
Cp*Co
III
(CO)I
2
has
been
found
to
effectively
catalyze
the
diamination
of
α‐alkyl
styrenes
with
anilines
under
a
mild
reaction
condition,
using
dioxygen
as
oxidant.
This
features
reasonably
good
substrate
scope
amines
and
functional
group
tolerance.
Preliminary
mechanistic
studies
have
shown
that
alone
can
promote
reaction.
