6 research outputs found
Gold-Catalyzed Cyclization of 3‑(2′-Azidoaryl)-1-arylpropargyl Carbonates or 3‑Aryl-1-(2′-azidoaryl)propargyl Carbonates to Produce Quinolines
A gold-catalyzed cyclization of 3-(2′-azidoaryl)-1-arylpropargyl
carbonates to generate substituted quinolines via a sequence of 3,3-rearrangement,
6-<i>endo</i>-trig cyclization and denitrogenation has been
developed. Similar products could be obtained from 3-aryl-1-(2′-azidoaryl)Âpropargyl
carbonates under different gold catalytic conditions via a sequential
6-<i>endo</i>-dig cyclization, denitrogenation, and 1,2-H
shift process
Gold-Catalyzed Cyclization of 3‑(2′-Azidoaryl)-1-arylpropargyl Carbonates or 3‑Aryl-1-(2′-azidoaryl)propargyl Carbonates to Produce Quinolines
A gold-catalyzed cyclization of 3-(2′-azidoaryl)-1-arylpropargyl
carbonates to generate substituted quinolines via a sequence of 3,3-rearrangement,
6-<i>endo</i>-trig cyclization and denitrogenation has been
developed. Similar products could be obtained from 3-aryl-1-(2′-azidoaryl)Âpropargyl
carbonates under different gold catalytic conditions via a sequential
6-<i>endo</i>-dig cyclization, denitrogenation, and 1,2-H
shift process
Gold-Catalyzed Cyclization of 3‑(2′-Azidoaryl)-1-arylpropargyl Carbonates or 3‑Aryl-1-(2′-azidoaryl)propargyl Carbonates to Produce Quinolines
A gold-catalyzed cyclization of 3-(2′-azidoaryl)-1-arylpropargyl
carbonates to generate substituted quinolines via a sequence of 3,3-rearrangement,
6-<i>endo</i>-trig cyclization and denitrogenation has been
developed. Similar products could be obtained from 3-aryl-1-(2′-azidoaryl)Âpropargyl
carbonates under different gold catalytic conditions via a sequential
6-<i>endo</i>-dig cyclization, denitrogenation, and 1,2-H
shift process
Asymmetric Total Syntheses of Aspidodasycarpine, Lonicerine, and the Proposed Structure of Lanciferine
Aspidodasycarpine
and lonicerine are a pair of epimeric aspidophylline-type
alkaloids bearing vicinal quaternary C7 and C16. The first and enantioselective
total syntheses of these molecules are described here. A Ru-catalyzed
asymmetric transfer hydrogenation established the first stereocenter.
An Au-promoted Toste cyclization was exploited to assemble the bridged
tetracyclic core and define the geometry of the exocyclic olefin;
electron deficient (<i>p</i>-CF<sub>3</sub>C<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P was a suitable ligand for this transformation.
An aldol condensation followed by an intramolecular indole C3 alkylation
constructed the adjacent quaternary C7 and C16 diastereoselectively,
leading to a pentacyclic lactol as an advanced common intermediate
for synthesizing both alkaloids. The proposed structure of lanciferine,
a highly oxidized congener of aspidodasycarpine, was synthesized from
the lactol by tuning the oxidation states of various carbons
Total Synthesis of Trioxacarcins DC-45-A1, A, D, C, and C7″-<i>epi</i>-C and Full Structural Assignment of Trioxacarcin C
Trioxacarcins
DC-45-A2, DC-45-A1, A, D, C7″-<i>epi</i>-C, and C
have been synthesized through stereoselective strategies
involving BF<sub>3</sub>·Et<sub>2</sub>O-catalyzed ketone–epoxide
opening and gold-catalyzed glycosylation reactions, and the full structural
assignment of trioxacacin C was deciphered via the syntheses of both
of its C7″ epimers. The gathered knowledge sets the foundation
for the design, synthesis, and biological evalution of analogues of
these natural products as potential payloads for antibody–drug
conjugates and other delivery systems for targeted and personalized
cancer chemotherapy
Streamlined Total Synthesis of TrioxaÂcarcins and Its Application to the Design, Synthesis, and Biological Evaluation of Analogues Thereof. Discovery of Simpler Designed and Potent TrioxaÂcarcin Analogues
A streamlined total synthesis of
the naturally occurring antitumor
agents trioxaÂcarcins is described, along with its application
to the construction of a series of designed analogues of these complex
natural products. Biological evaluation of the synthesized compounds
revealed a number of highly potent, and yet structurally simpler,
compounds that are effective against certain cancer cell lines, including
a drug-resistant line. A novel one-step synthesis of anthraÂquinones
and chloro anthraÂquinones from simple ketone precursors and
phenylÂselenyl chloride is also described. The reported work,
featuring novel chemistry and cascade reactions, has potential applications
in cancer therapy, including targeted approaches as in antibody–drug
conjugates