Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles

Rsuini U Gutiérrez; Mayra Hernández-Montes; Aarón Mendieta-Moctezuma; Francisco Delgado; Joaquín Tamariz

doi:10.3390/molecules26134092

Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles

Molecules. 2021 Jul 5;26(13):4092. doi: 10.3390/molecules26134092.

Authors

Rsuini U Gutiérrez¹, Mayra Hernández-Montes¹, Aarón Mendieta-Moctezuma², Francisco Delgado¹, Joaquín Tamariz¹

Affiliations

¹ Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, Mexico City 11340, Mexico.
² Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla, Km 1.5, Tlaxcala 90700, Mexico.

Abstract

An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cyclization of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H activation. In a single-step approach, a variety of 2-substituted indoles were also generated via a Hg(I)/Pd(II)-catalyzed, one-pot, two-step process, starting from anilines and terminal acetylenes. The arylacetylenes proved to be more effective than the alkyl derivatives.

Keywords: Pd-catalyzed oxidative cyclization; imines; mercury(I)-catalyzed alkyne hydroamination; one-pot indole synthesis.