Metal-Ligand Cooperative Approach To Achieve Dehydrogenative Functionalization of Alcohols to Quinolines and Quinazolin-4(3 H)-ones under Mild Aerobic Conditions

Siuli Das; Suman Sinha; Deepannita Samanta; Rakesh Mondal; Gargi Chakraborty; Paula Brandaõ; Nanda D Paul

doi:10.1021/acs.joc.9b01343

Metal-Ligand Cooperative Approach To Achieve Dehydrogenative Functionalization of Alcohols to Quinolines and Quinazolin-4(3 H)-ones under Mild Aerobic Conditions

J Org Chem. 2019 Aug 16;84(16):10160-10171. doi: 10.1021/acs.joc.9b01343. Epub 2019 Aug 2.

Authors

Siuli Das¹, Suman Sinha¹, Deepannita Samanta¹, Rakesh Mondal¹, Gargi Chakraborty¹, Paula Brandaõ², Nanda D Paul¹

Affiliations

¹ Department of Chemistry , Indian Institute of Engineering Science and Technology , Shibpur, Botanic Garden, Howrah 711103 , West Bengal , India.
² Departamento de Química, CICECO-Instituto de Materiais de Aveiro , Universidade de Aveiro , 3810-193 Aveiro , Portugal.

PMID: 31327228
DOI: 10.1021/acs.joc.9b01343

Abstract

A simple metal-ligand cooperative approach for the dehydrogenative functionalization of alcohols to various substituted quinolines and quinazolin-4(3H)-ones under relatively mild reaction conditions (≤90 °C) is reported. Simple and easy-to-prepare air-stable Cu(II) complexes featuring redox-active azo-aromatic scaffolds, 2-arylazo-(1,10-phenanthroline) (L^1,2), are used as catalyst. A wide variety of substituted quinolines and quinazolin-4(3H)-ones were synthesized in moderate to good isolated yields via dehydrogenative coupling reactions of various inexpensive and easily available starting materials under aerobic conditions. A few control experiments and deuterium labeling studies were carried out to understand the mechanism of the dehydrogenative coupling reactions, which indicate that both copper and the coordinated azo-aromatic ligand participate in a cooperative manner during the catalytic cycle.