Theoretical Studies on the Competing Mechanism and Origin of Diastereoselectivity of NHC-Catalyzed Intramolecular [3 + 2] Annulations of Ynals
The Journal of Physical Chemistry A,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 5, 2025
Chiral
tricyclic
6,5,5-fused
rings
exhibit
structural
diversity
and
possess
important
biological
activities
in
the
synthesis
of
natural
products.
However,
predicting
possible
mechanism
origin
stereoselectivity
these
reactions
remains
a
challenge.
In
this
article,
we
conducted
theoretical
investigation
into
NHC-catalyzed
intramolecular
[3
+
2]
annulations
ynals
to
generate
rings.
Our
calculations
revealed
that
NHC
could
nucleophilically
attack
carbonyl
group
ynal
reactant,
leading
formation
Breslow
intermediate
via
1,2-proton
transfer.
Subsequently,
an
Michael
addition
takes
place,
resulting
6-5
bicyclic
intermediate.
We
then
compared
competitive
processes
involving
proton
transfer
Mannich
reaction.
The
more
energetically
favorable
process
involves
HOAc-assisted
process,
followed
by
To
ascertain
diastereoselectivity,
performed
noncovalent
interaction
(NCI)
atom-in-molecule
(AIM)
analyses.
This
work
is
useful
for
understanding
general
principles
detailed
mechanisms
chiral
scaffolds
with
unique
diastereoselectivity.
Язык: Английский
NHC‐Catalyzed Asymmetric Intramolecular [3+2] Annulations of Cyclohexadienone‐Tethered Ynals
Asian Journal of Organic Chemistry,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 3, 2025
Abstract
NHC‐Catalyzed
enantioselective
conversion
of
ynals
remains
challenging
through
nucleophilic
NHC‐allenolate
intermediates.
Herein,
we
present
an
NHC‐catalyzed
highly
asymmetric
intramolecular
[3+2]
annulation
cyclohexadienone‐tethered
ynals.
This
reaction
enables
a
rapid
and
efficient
construction
6,5,5‐tricyclic
frameworks
bearing
three
contiguous
stereocenters
in
excellent
enantioselectivities.
Additionally,
the
synthetic
utility
is
elaborated
gram‐scale
experiment
several
downstream
transformations.
Язык: Английский
Synthesis of 6/5/3-Fused Tricyclic Scaffolds via Multistep Cascade Cyclization of α-Aryl Vinylsulfoniums with para-Quinamines and para-Quinols
Organic Letters,
Год журнала:
2024,
Номер
26(28), С. 5905 - 5910
Опубликована: Июль 9, 2024
Herein,
we
present
a
straightforward
approach
to
access
hydroindoline-5-one-based
6/5/3-fused
polycyclic
ring
structures
through
multistep
cascade
reactions
involving
α-aryl
vinylsulfoniums
and
Язык: Английский
N-Heterocyclic Carbenes Catalyze the Formation of Fused 6-5-5 Tricyclic Natural-Product Frameworks
Synfacts,
Год журнала:
2024,
Номер
20(07), С. 0744 - 0744
Опубликована: Июнь 14, 2024
Key
words
N-heterocyclic
carbenes
-
annulation
tricycloundecanes
ynals
Язык: Английский
N‐Heterocyclic Carbene Catalyzed Reactions Involving Acetylenic Breslow and/or Acylazolium as Key Intermediates
The Chemical Record,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 19, 2024
N-heterocyclic
carbene
(NHC)
organocatalysis
has
been
developed
as
a
powerful
tool
in
modern
synthetic
chemistry.
NHC
catalytic
activation
of
ynals
and
alkynoic
acid
derivatives
provided
versatile
reactions
that
involve
acetylenic
Breslow
and/or
acylazolium
key
intermediates,
diverse
transformations
have
established
for
access
to
molecules
with
unique
skeletons
efficient
fashions.
Herein
we
summarize
the
recent
achievements
NHC-catalyzed
involving
intermediates.
Different
belonging
three
modes,
including
(1)
conjugate
additions
derived
α,β-unsaturated
(2)
β-umpolung
via
(3)
are
emphasized
examples
plausible
mechanisms
cited
guide
better
understanding.
Язык: Английский