Ionic liquids in catalysis

The key attribute of the thiol-Michael addition reaction that makes it a prized tool in materials science is its modular “click” nature, which allows for the implementation of this highly efficient, “green” reaction in applications that vary from small molecule synthesis to in situ polymer modifications in biological systems to the surface functionalization of material coatings. Over the past few decades, interest in the thiol-Michael addition reaction has increased dramatically, as is evidenced by the number of studies that have been dedicated to elucidating different aspects of the reaction that range from an in-depth analysis aimed at understanding the mechanistic pathways of the reaction to synthetic studies that have examined modifying molecular structures with the aim of yielding highly efficient thiol-Michael reaction monomers. This review examines the reaction mechanisms, the substrates and catalysts used in the reaction, and the subsequent implementation of the thiol-Michael reaction in materials...

The Thiol-Michael Addition Click Reaction: A Powerful and Widely Used Tool in Materials Chemistry

Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Green Chemistry Center, Peking University, 202 Chengfu Road, 098#, Beijing 100871, China State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 200060, China

Transition-Metal-Free Coupling Reactions

Nucleophilic ring opening of aziridines

Chemical and biochemical transformations in ionic liquids

[Bmim]BF4 ionic liquid: a novel reaction medium for the synthesis of β-amino alcohols

α,β-Unsaturated ketones undergo conjugate addition rapidly with thiols in a hydrophobic ionic liquid [bmim]PF6/H2O solvent system (2:1) in the absence of any acid catalyst to afford the corresponding Michael adducts in high to quantitative yields with excellent 1,4-selectivity under mild and neutral conditions. The enones show enhanced reactivity in ionic liquids, thereby reducing reaction times and improving the yields significantly. The use of ionic liquids helps to avoid the use of either acid or base catalysts for this conversion. The recovered ionic liquid was reused four to five times with consistent activity.

Green Protocol for Conjugate Addition of Thiols to α,β-Unsaturated Ketones Using a [Bmim]PF6/H2O System

Conjugate addition of indoles to α,β-unsaturated ketones using Cu(OTf)2 immobilized in ionic liquids

Epoxides react smoothly with thiols in the presence of 10 mol% InCl3 under very mild conditions to afford the corresponding β-hydroxy sulfides in high yields with high regioselectivity. Similar yields and selectivity are also obtained with catalytic amount of indium triflate under these reaction conditions.

Buthukuri Venkat Reddy

Papers

[Bmim]BF4 ionic liquid: a novel reaction medium for the synthesis of β-amino alcohols

Green Protocol for Conjugate Addition of Thiols to α,β-Unsaturated Ketones Using a [Bmim]PF6/H2O System

Conjugate addition of indoles to α,β-unsaturated ketones using Cu(OTf)2 immobilized in ionic liquids

InCl3-Catalyzed Highly Regioselective Ring Opening of Epoxides with Thiols

[Bmim]PF6 and BF4 ionic liquids as novel and recyclable reaction media for aromatic amination