Access to Cyclobutene-Fused Azepines through Au-Catalyzed Cycloisomerization of Stable Alkyne Tethered Ketene <i>N,N</i>-Acetals

A base promoted reaction between N-protected propargyl amines and 3-bromopropiolate readily provides an array of novel stable alkyne-tethered ketene <i>N,N</i>-acetals in good yields. A wide range of structurally complex cyclobutene-fused azepine heterocycles are synthesized through the gold-catalyzed intramolecular cycloisomerization of ketene <i>N,N</i>-acetals for the first time. A plausible reaction pathway is deduced on the basis of the ¹H NMR studies

Leveraging Zn(II) Catalyst: Synthesis of Amidoquinolines via (3 + 3) Heteroannulation of Aromatic Amines and Ynamides

Herein, we present a Zn­(II)-catalyzed (3 + 3) heteroannulation reaction between aromatic amines and 1,3-diynamides for the synthesis of amidoquinolines. A large number of aromatic amines are well tolerated, furnishing quinoline derivatives in up to excellent yield. Notably, various reactive functional groups have survived under the optimal reaction conditions, highlighting the mildness of the developed protocol. In addition, amines derived from bioactive molecules show modest reactivity

Leveraging Zn(II) Catalyst: Synthesis of Amidoquinolines via (3 + 3) Heteroannulation of Aromatic Amines and Ynamides

Herein, we present a Zn­(II)-catalyzed (3 + 3) heteroannulation reaction between aromatic amines and 1,3-diynamides for the synthesis of amidoquinolines. A large number of aromatic amines are well tolerated, furnishing quinoline derivatives in up to excellent yield. Notably, various reactive functional groups have survived under the optimal reaction conditions, highlighting the mildness of the developed protocol. In addition, amines derived from bioactive molecules show modest reactivity

<i>p</i>‑TsOH Promoted Au(I)-Catalyzed Consecutive Endo Cyclization of Yne-Tethered Ynamide: Access to Benzofused Dihydroisoquinolones

A novel synthetic route to benzo­[<i>f</i>]­dihydro­isoquinolone through a <i>p</i>-TsOH promoted cascade cyclization of easily accessible diyne-tethered ynamides in the presence of a Au­(I)-catalyst is described. This reaction unveils a broad substrate scope, constructing a wide range of benzo­[<i>f</i>]­dihydro­isoquinolones in good yields. The diyne-tethered ynamides are synthesized from inexpensive <i>o</i>-iodoaniline through Sonogashira couplings and the Cu-mediated C–N bond formation. The role of <i>p</i>-TsOH is examined, and the reaction pathway is also deduced. The benzo­[<i>f</i>]­isoquinoline scaffold is constructed from benzo­[<i>f</i>]­dihydro­isoquinolones

<i>p</i>‑TsOH Promoted Au(I)-Catalyzed Consecutive Endo Cyclization of Yne-Tethered Ynamide: Access to Benzofused Dihydroisoquinolones

A novel synthetic route to benzo­[<i>f</i>]­dihydro­isoquinolone through a <i>p</i>-TsOH promoted cascade cyclization of easily accessible diyne-tethered ynamides in the presence of a Au­(I)-catalyst is described. This reaction unveils a broad substrate scope, constructing a wide range of benzo­[<i>f</i>]­dihydro­isoquinolones in good yields. The diyne-tethered ynamides are synthesized from inexpensive <i>o</i>-iodoaniline through Sonogashira couplings and the Cu-mediated C–N bond formation. The role of <i>p</i>-TsOH is examined, and the reaction pathway is also deduced. The benzo­[<i>f</i>]­isoquinoline scaffold is constructed from benzo­[<i>f</i>]­dihydro­isoquinolones

Regioselective Hydration of Terminal Halo-Substituted Propargyl Carboxylates by Gold Catalyst: Synthesis of α‑Acyloxy α′-Halo Ketones

Regioselective hydration of the terminal halo-substituted propargyl carboxylate by gold­(I) catalyst is reported. The mild catalytic conditions tolerate common acid-labile protecting groups, and a wide variety of α-acyloxy α′-halo ketones are efficiently synthesized within a short reaction time. The α-acyloxy α′-halo ketones are used for the synthesis of 2-aminothiazoles

Copper/Zinc-Catalyzed Stitching of 2‑Carbonylanilines with Bis(ynamides): Access to Pyrrolo[2,3‑<i>b</i>]quinolines and Its Photophysical Studies

Herein, a one-pot desulfonylative protocol enabled by copper(II)/zinc(II) salts to access pyrrolo[2,3-b]quinolines in good to excellent yields from 2-carbonylanilines and ynamide-derived buta-1,3-diynes has been reported. Significantly, various 2-carbonylanilines carrying reactive functional groups are well tolerated. Moreover, a gram-scale synthesis and synthetic application highlight the practical utility of the current protocol. Notably, the fluorescence properties of pyrrolo[2,3-b]quinolines have been recorded, and their potential use as a fluorescent probe in the imaging of live cells has been demonstrated

Copper/Zinc-Catalyzed Stitching of 2‑Carbonylanilines with Bis(ynamides): Access to Pyrrolo[2,3‑<i>b</i>]quinolines and Its Photophysical Studies

Herein, a one-pot desulfonylative protocol enabled by copper(II)/zinc(II) salts to access pyrrolo[2,3-b]quinolines in good to excellent yields from 2-carbonylanilines and ynamide-derived buta-1,3-diynes has been reported. Significantly, various 2-carbonylanilines carrying reactive functional groups are well tolerated. Moreover, a gram-scale synthesis and synthetic application highlight the practical utility of the current protocol. Notably, the fluorescence properties of pyrrolo[2,3-b]quinolines have been recorded, and their potential use as a fluorescent probe in the imaging of live cells has been demonstrated