Organic Letters,
Journal Year:
2022,
Volume and Issue:
24(2), P. 675 - 680
Published: Jan. 10, 2022
Asymmetric
hydrogenation
of
tetrasubstituted
alkenes
remains
a
formidable
challenge
in
asymmetric
catalysis.
We
report
herein
an
unprecedented
Rh-catalyzed
enantioselective
and
diastereoselective
easily
accessed
α,β-disubstituted
unsaturated
lactams
to
afford
synthetically
valuable
chiral
with
1,2-consecutive
stereocenters.
The
reaction
could
be
performed
on
the
gram
scale,
products
concisely
transformed
enantiomerically
pure
trans-3,4-disubstituted
piperidines,
which
are
prevalent
structural
units
medicinal
agents.
Green Chemistry,
Journal Year:
2023,
Volume and Issue:
25(3), P. 1067 - 1077
Published: Jan. 1, 2023
Under
illumination
with
450
nm
light,
porous
BiVO
4
photoelectrodes
support
photoeletrochemical
Kolbe
coupling
up
to
near
quantitative
faradaic
efficiency
and
apparent
quantum
yield
of
12%
at
applied
voltages
<2
V.
Chemistry - A European Journal,
Journal Year:
2023,
Volume and Issue:
29(55)
Published: June 26, 2023
Introduction
of
Crabtree's
iridium-based
hydrogenation
catalyst
in
1977
marked
a
paradigm
shift
both
with
respect
to
the
role
iridium
homogeneous
catalysis
as
well
catalytic
olefins.
In
1998,
Pfaltz
introduced
an
improved
catalyst,
by
use
BARF-
anion,
and
established
first
chiral
variant
Crabtree
catalyst.
This
led
numerous
practical
highly
enantioselective
syntheses.
Elucidation
mechanistic
details
posed
great
problems
because
instability
crucial
intermediates.
A
remarkable
breakthrough
was
achieved
Brandt,
Andersson
et
al.
2003,
based
on
dft
calculations.
These
authors
replaced
previously
assumed
IrI
/IrIII
cycle
novel
IrIII
/IrV
cycle.
The
proposal
experimentally
verified
2014
corroborated
advanced
quantum
chemical
essay
is
attempt
describe
fascinating
interplay
experiments
calculations
for
important
synthetic
method.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
63(9)
Published: Dec. 14, 2023
Asymmetric
hydrogenation
(AH)
of
tetrasubstituted
olefins
generating
two
stereocenters
is
still
an
open
topic.
There
are
only
a
few
reports
on
the
AH
with
conjugated
functional
groups,
while
this
process
can
create
useful
intermediates
for
subsequent
elaboration
relevant
end
products.
Most
successfully
submitted
to
belong
small
number
classes;
remarkably,
acyclic
enones
represents
unsolved
challenge.
Herein,
we
disclose
class
air-stable
Ir-P,N
catalysts,
prepared
in
three
steps
from
commercially
available
amino
alcohols,
that
hydrogenate,
minutes,
wide
range
electronically
and
sterically
diverse
(including
exocyclic
ones)
high
yields
enantioselectivities.
The
factors
responsible
excellent
selectivities
were
elucidated
by
combining
deuterogenation
experiments
theoretical
calculations.
calculations
indicated
reduction
follows
Ir
Organic Letters,
Journal Year:
2021,
Volume and Issue:
23(18), P. 7166 - 7170
Published: Sept. 1, 2021
Because
of
the
formidable
development
asymmetric
reduction
tetrasubstituted
olefins,
an
effective
method
is
in
urgent
demand.
Herein,
through
biomimetic
protocol
coenzyme
NAD(P)H,
olefin
2,3-substituted
1H-inden-1-ones
has
been
successfully
realized
with
catalytic
chiral
NAD(P)H
model
CYNAM,
which
hard
to
bring
about
via
common
rhodium
or
iridium-based
system,
producing
corresponding
products
good
yield
(up
98%)
enantioselectivity
99%
ee).
Furthermore,
bioactive
molecule
can
be
concisely
synthesized
from
reduced
product.
Organic Letters,
Journal Year:
2022,
Volume and Issue:
24(2), P. 675 - 680
Published: Jan. 10, 2022
Asymmetric
hydrogenation
of
tetrasubstituted
alkenes
remains
a
formidable
challenge
in
asymmetric
catalysis.
We
report
herein
an
unprecedented
Rh-catalyzed
enantioselective
and
diastereoselective
easily
accessed
α,β-disubstituted
unsaturated
lactams
to
afford
synthetically
valuable
chiral
with
1,2-consecutive
stereocenters.
The
reaction
could
be
performed
on
the
gram
scale,
products
concisely
transformed
enantiomerically
pure
trans-3,4-disubstituted
piperidines,
which
are
prevalent
structural
units
medicinal
agents.
