One-Pot Synthesis of Multisubstituted 2-Aminoquinolines from Annulation of 1-Aryl Tetrazoles with Internal Alkynes via Double C–H Activation and Denitrogenation

Abstract

An efficient, one-pot synthesis of multisubstituted 2-aminoquinolines from 1-aryl tetrazoles and internal alkynes has been developed. The reaction involves cyclization of 1-aryl tetrazoles with internal alkynes via rhodium(III)-catalyzed double C-H activation and copper(II)-mediated denitrogenation.

Synthesis of 2‐Substituted Quinolines via Rhodium(III)‐Catalyzed C–H Activation of Imidamides and Coupling with Cyclopropanols

“…In 2011, we reported the rhodium(III)‐catalyzed two‐fold C–H activation of functionalized pyridines and coupling with two alkyne molecules for the synthesis of polysubstituted quinolines (Scheme ) . Hua reported a tandem C–H activation and denitrogenative annulation between 1‐aryltetrazoles and internal alkynes for the synthesis of substituted 2‐aminoquinolines . Moreover, Miura, Chen, and You have reported the synthesis of aza‐fused polycyclic quinolines via Cp*Rh(III) catalysis.…”

Metal‐Free Synthesis of Alkenylazaarenes and 2‐Aminoquinolines through Base‐Mediated Aerobic Oxidative Dehydrogenation of Benzyl Alcohols

“…Finally, to exemplify the utility of the 2‐aminoquinoline derivatives, in a representative reaction compound 10 aa was treated with acetophenone in the presence of Cu(OAc) 2 and ZnI in dichlorobenzene to produce 2,4‐diphenylimidazo[1,2‐ a ]quinolone 16 in 32 % yield together with the recovery of starting material (58 %) (Scheme 7). [19] …”

Isoquinolone Synthesis via Zn(OTf)2-Catalyzed Aerobic Cyclocondensation of 2-(1-Alkynyl)-benzaldehydes with Arylamines

“…Encouraged by the results obtained above, we studied the substrate scope for the formation of isoquinolin-1(2H)-ones using various ortho-alkynylbenzaldehydes and amines bearing different substituents under the conditions of entry 6 in Table 1. As can be seen from Table 2, βaminonaphthalene (2b), para-substituted anilines (para-Me, 2c; parai Pr, 2d; para-Br, 2f), 2-methyl-3methoxyaniline (3e), and 2,4-difluoroaniline (2g) underwent cyclocondensation with 1a affording the Recently, we have been interested in the applications of 2-(1-alkynyl)benzaldehydes in the synthesis of benzo-fused cyclic compounds [28,33,39], air-stable Lewis acids as catalysts in organic transformation [40][41][42][43][44], and the development of synthetic methods for the formation of nitrogen-heterocyclic compounds via alkyne annulations [45][46][47][48][49][50][51][52][53]. Therefore, in continuation of our interests in the application of 2-(1-alkynyl)benzaldehydes, we herein describe a simple and efficient method for the construction of isoquinolone from the cyclocondensation of 2-(1-alkynyl)benzaldehydes with arylamines in the presence of a catalytic amount of Zn(OTf) 2 (Scheme 1, eq.…”