Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

László Orha; József M Tukacs; László Kollár; László T Mika

doi:10.3762/bjoc.15.284

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

Beilstein J Org Chem. 2019 Dec 3:15:2907-2913. doi: 10.3762/bjoc.15.284. eCollection 2019.

Authors

László Orha^{1

2}, József M Tukacs¹, László Kollár³, László T Mika¹

Affiliations

¹ Department of Chemical and Environmental Process Engineering, Budapest University of Technology and Economics Műegyetem rkp. 3, Budapest, H-1111, Hungary.
² Institute of Isotopes, Konkoly-Thege Miklós str. 29-33. Budapest, H-1121, Hungary.
³ Department of Inorganic Chemistry, University of Pécs and János Szentágothai Research Center and MTA-PTE Research Group for Selective Chemical Syntheses, Ifjúság u. 6.; Pécs, H-7624, Hungary.

Abstract

It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72-99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.

Keywords: catalysis; cross coupling; green chemistry; ionic liquids.