44 research outputs found
Synthesis of Fused Pyran Derivatives via Visible-Light-Induced Cascade Cyclization of 1,7-Enynes with Acyl Chlorides
A photocatalytic cascade cyclization
of 1,7-enynes with acyl chlorides
has been established. This method offers an operationally simple access
to diverse fused pyran derivatives with a broad substrate scope in
high yields from simple acyl chlorides via an acyl radical intermediate
Synthesis of Fused Pyran Derivatives via Visible-Light-Induced Cascade Cyclization of 1,7-Enynes with Acyl Chlorides
A photocatalytic cascade cyclization
of 1,7-enynes with acyl chlorides
has been established. This method offers an operationally simple access
to diverse fused pyran derivatives with a broad substrate scope in
high yields from simple acyl chlorides via an acyl radical intermediate
α‑Oxo-γ-Butyrolactam, <i>N</i>‑Containing Pronucleophile in Organocatalytic One-Pot Assembly of Butyrolactam-Fused Indoloquinolizidines
The ambident reactivity of α-oxo-γ-butyrolactam
has
been explored in an organocatalytic one-pot Michael/Pictet–Spengler
sequence. The synthetically interesting and medicinally important
pentacyclic butyrolactam-fused indoloquinolizidines can be efficiently
constructed in a highly stereocontrolled manner. Importantly, the
chemistry described herein provides a general catalytic method for
the enantioselective synthesis of butyrolactam-incorporated chemical
entities
α‑Oxo-γ-Butyrolactam, <i>N</i>‑Containing Pronucleophile in Organocatalytic One-Pot Assembly of Butyrolactam-Fused Indoloquinolizidines
The ambident reactivity of α-oxo-γ-butyrolactam
has
been explored in an organocatalytic one-pot Michael/Pictet–Spengler
sequence. The synthetically interesting and medicinally important
pentacyclic butyrolactam-fused indoloquinolizidines can be efficiently
constructed in a highly stereocontrolled manner. Importantly, the
chemistry described herein provides a general catalytic method for
the enantioselective synthesis of butyrolactam-incorporated chemical
entities
Visible-Light-Induced Aza-Pinacol Rearrangement: Ring Expansion of Alkylidenecyclopropanes
A novel visible-light-induced aza-pinacol
rearrangement was developed
for the first time. In this approach, the addition of the N-centered
radical to the Cî—»C bond of alkylidenecyclopropanes delivers
a variety of cyclobutanimines and γ-butyrolactones, with all-carbon
quaternary centers via the ring expansion of the cyclopropyl group,
in moderate to good yields under mild reaction conditions
Visible-Light-Induced Alkoxypyridylation of Alkenes Using N‑Alkoxypyridinium Salts as Bifunctional Reagents
Considering
the ubiquitous presence of pyridine moieties in pharmaceutical
compounds, it holds immense value to develop practical and straightforward
methodologies for accessing heterocyclic aromatic hydrocarbons. In
recent years, N-alkoxypyridinium salts have emerged as convenient
radical precursors, enabling the generation of the corresponding alkoxy
radicals and pyridine through single-electron transfer. Herein, we
present the first report on visible-light-mediated intermolecular
alkoxypyridylation of alkenes employing N-alkoxylpyridinium salts
as bifunctional reagents with an exceptionally low catalyst loading
(0.5 mol %)
TiCl<sub>4</sub> Promoted Formal [3 + 3] Cycloaddition of Cyclopropane 1,1-Diesters with Azides: Synthesis of Highly Functionalized Triazinines and Azetidines
A TiCl<sub>4</sub> promoted formal [3 + 3] cycloaddition of cyclopropane
1,1-diesters with azides has been developed for the synthesis of highly
functionalized triazinines. Both stoichiometric and substoichiometric
versions of this reaction were accomplished dependent on the choice
of solvent. It is noteworthy that the corresponding products could
be easily converted to biologically important azetidines by simple
thermolysis
3,4,5-Trimethylphenol and Lewis Acid Dual-Catalyzed Cascade Ring-Opening/Cyclization: Direct Synthesis of Naphthalenes
A 3,4,5-trimethylphenol
and Lewis acid dual-catalyzed cascade reaction
of donor–acceptor (D–A) cyclopropanes via ring-opening
and cyclization is developed. In this reaction, a phenolic compound
was used as a covalent catalyst for the first time. Additionally,
control experiments proved that 3,4,5-trimethylphenol completed the
catalytic cycle by accomplishing the C–C bond cleavage. Using
this strategy, a wide variety of substituted naphthalenes has been
synthesized from D–A cyclopropanes in moderate to high yields
under mild conditions
Rh(II) Catalyzed High Order Cycloadditions of 8‑Azaheptafulvenes with <i>N</i>‑Sulfonyl 1,2,3-Triazloes or α‑Oxo Diazocompounds
A novel strategy
was developed for the application of Rh carbenes
generated from readily accessible <i>N</i>-sulfonyl 1,2,3,-triazoles
or diazocompouds in the high order cycloadditions, which offered an
efficient route to a variety of N-containing medium-sized rings. The
process provided a wide range of cycloÂheptaÂ[<i>b</i>]Âpyrazine and cycloÂheptaÂ[<i>b</i>]Âpyrrolone
derivatives with high yields