A copper(ii)-catalyzed annulative formylation of o-alkynylanilines with DMF: a single-step strategy for 3-formyl indoles

Balaji Ganesan; Gopal Chandru Senadi; Bing-Chun Guo; Min-Yuan Hung; Wei-Yu Lin

doi:10.1039/c8ra09214a

A copper(ii)-catalyzed annulative formylation of o-alkynylanilines with DMF: a single-step strategy for 3-formyl indoles

RSC Adv. 2018 Dec 7;8(71):40968-40973. doi: 10.1039/c8ra09214a. eCollection 2018 Dec 4.

Authors

Balaji Ganesan¹, Gopal Chandru Senadi^{1

2}, Bing-Chun Guo¹, Min-Yuan Hung³, Wei-Yu Lin¹

Affiliations

¹ Department of Medicinal and Applied Chemistry, Kaohsiung Medical University No. 100 Shi-chuan, 1st Road Kaohsiung 807 Taiwan wylin@kmu.edu.tw.
² Department of Chemistry, SRM Institute of Science and Technology Kattankulathur Chennai-603203 India.
³ Center for Research Resources and Development, Kaohsiung Medical University No. 100 Shi-chuan, 1st Road Kaohsiung 807 Taiwan.

Abstract

In this paper, a copper(ii)-catalyzed reaction of o-alkynylanilines with dimethylformamide (DMF) in the presence of oxygen has been developed for synthesizing multisubstituted 3-formyl indole scaffolds. This one-pot reaction proceeds through a cascade 5-endo-dig cyclization followed by formylation to construct 1,2-disubstituted 3-formyl indoles. The key aspects of this synthesis method are the broad substrate scope (with 38 examples), and well tolerating various functional groups. In addition, a detailed mechanism has been proposed, where DMF may serve as a carbon source for the in situ C3 formylation of the obtained indole derivatives.