Synthesis of Polysubstituted Quinolines from α-2-Aminoaryl Alcohols Via Nickel-Catalyzed Dehydrogenative Coupling

Abstract

This study reports a nickel-catalyzed sustainable synthesis of polysubstituted quinolines from α-2-aminoaryl alcohols by a sequential dehydrogenation and condensation process that offers the advantages of a low catalyst loading and wide substrate scope. In contrast to earlier reported methods, this strategy allows the use of both primary as well as secondary α-2-aminoaryl alcohols in combination with either ketones or secondary alcohols for desired product formation. Using this methodology, 30 substituted quinoline derivatives were synthesized with up to 93% isolated yields.

Nickel‐Catalyzed Dehydrogenative Couplings

“…De Sarkar and Nanda independently reported an operationally simple procedure to prepare various polysubstituted quinolines from simple alcohol precursors (Scheme ). The acceptorless dehydrogenative process was efficiently carried out earth abundant Ni‐catalyst [Ni(MeTAA)].…”

Base‐Promoted Aerobic Oxidation/Homolytic Aromatic Substitution Cascade toward the Synthesis of Phenanthridines

“…In our ongoing research program towards the sustainable synthesis of heteroaryl compounds, [16] we envisioned base-promoted aerial oxidation [17] followed by homolytic aromatic substitution cascade for the synthesis of phenanthridine derivatives (Scheme 1b). This transition metal-free approach would allow the direct use of alcohols [18] and 2-iodoaniline derivatives.…”

“…[13] In 2011, Bin Li first synthesized phenanthridines from imine substrate using Pd-catalyzed intramolecular CÀ H activation/CÀ C cross-coupling, [14] subsequently Kwong group reported a transition-metal-free procedure. In our ongoing research program towards the sustainable synthesis of heteroaryl compounds, [16] we envisioned base-promoted aerial oxidation [17] followed by homolytic aromatic substitution cascade for the synthesis of phenanthridine derivatives (Scheme 1b). In our ongoing research program towards the sustainable synthesis of heteroaryl compounds, [16] we envisioned base-promoted aerial oxidation [17] followed by homolytic aromatic substitution cascade for the synthesis of phenanthridine derivatives (Scheme 1b).…”

A review on transition-metal mediated synthesis of quinolines

“…This protocol involves the reaction of both primary/secondary α-2aminoaryl alcohols (221) either with ketones (222)/secondary alcohols (223) and occurred through C-N and C-C bonds formations using low catalytic loading (Scheme 83). 111 This pathway is cost-effective, efficient and has good substrate scope to afford excellent yield of products. Further, the method is utilized to synthesize series of wide range of substituted quinolines.…”