Copper-Catalyzed Chemoselective Cyclization Reaction of 2-Isocyanoacetophenone: Synthesis of 4-Hydroxyquinoline Compounds

Abstract

A copper-catalyzed intramolecular cyclization reaction of 2-isocyano­aceto­phenone derivatives to afford 4-hydroxyquinolines chemoselectively is described. The transformation proceeds through enol tautomerism and a subsequent C–C bond formation. Compared to previous methods, this study provides a new protocol for the construction of 4-hydroxyquinoline compounds from functionalized isocyanides under mild conditions.

Synthesis of Quinazolin-4-ones by Copper-Catalyzed Isocyanide Insertion

“…However, the notably increased difficulty in the synthesis of electron-rich 5b and the relatively facile synthesis of 5e imply that the reactivity is inversely correlated to the electron density around the isocyanide carbon. Therefore, it is likely the copper catalyst acts more as a Lewis acid, which is in line with recent results reported by us, Zhu, and Ji …”

“…Therefore, it is likely the copper catalyst acts more as a Lewis acid, which is in line with recent results reported by us, 4c Zhu, 15 and Ji. 16 The synthetic utility of this methodology is underlined by the syntheses of several natural products in a single postinsertion/cyclocondensation reaction. First, we utilized our methodology to couple isocyanobenzoate 1a with ethanolamine (6) to afford the plant alkaloid echinozolinone 17 (7) in 90% yield (Scheme 6a).…”

Efficient Organoruthenium Catalysts for α‐Alkylation of Ketones and Amide with Alcohols: Synthesis of Quinolines via Hydrogen Borrowing Strategy and their Mechanistic Studies

“…1‐(2‐aminophenyl)‐3‐(4‐methoxyphenyl)propan‐1‐one (3 fg) Yield 234.9 mg 92 % (Catalyst Ru1 ), 229.8 mg 90 % (Catalyst Ru2 ); 1 H NMR (400 MHz, CDCl 3 ) δ 7.72 (d, J =8.1 Hz, 1H), 7.24 (t, J =8.4 Hz, 1H), 7.18–7.14 (m, 2H), 6.84 (d, J =8.6 Hz, 2H), 6.84–6.61 (m, 2H), 6.27 (s, 2H), 3.78 (s, 3H), 3.22 (t, J =8.3, 2H), 2.97 (t„ J =7.0 Hz 2H). 13 C NMR (101 MHz, CDCl 3 ) δ 201.84, 158.01, 150.45, 134.35, 133.59, 131.15, 129.41, 117.93, 117.46, 115.89, 114.00, 55.37, 41.35, 29.83.…”

Direct 1,1-Bisphosphonation of Isocyanides: Atom- and Step-Economical Access to Bisphosphinoylaminomethanes

“…Isocyanides are important building blocks in modern organic synthesis, which have been widely employed in the construction of various nitrogen-containing compounds because they are easy to handle and exhibit high reactivity. , Given our continuing interest in isocyanide chemistry, herein, we reported a highly efficient and straightforward isocyanide-based formal multicomponent reactions, which provide an atom- and step-economical strategy for preparing bisphosphinoylaminomethane derivatives under mild conditions­(Scheme d).…”