In water, on water, and by water: mimicking nature's aldolases with organocatalysis and water

Abstract

We review recent developments and applications of aldolase-type organocatalytic direct transformations in aqueous media without addition of organic solvent.

SN1‐Type Reactions in the Presence of Water: Indium(III)‐Promoted Highly Enantioselective Organocatalytic Propargylation of Aldehydes

“…and excellent enantiocontrol with alcohol 4 d. It is noteworthy that the use of water as the reaction medium is well-explored in organocatalysis. [19] Although we have not observed a dramatic acceleration of the reaction typical of "on water" conditions, [20] it is quite remarkable that the S N 1 reaction is not hampered by water and that the reaction is working only in the presence of indium salts.…”

l-Valine Dipeptide Organocatalysts with Two Amide Units for the Direct Asymmetric Aldol Reaction in Brine

“…On the other hand, the development of stereoselective reactions using water as reaction medium is another attractive research field [14,15], mainly due to the low cost, safety and environmentally benign nature of water. Therefore, a great deal of emphasis has been devoted to the development of water-tolerant organocatalyst for direct asymmetric aldol reaction, and some groups have reported organocatalytic direct asymmetric aldol in water without using any organic co-solvent [16][17][18][19].…”

Ionic Liquid Immobilized Organocatalysts for Asymmetric Reactions in Aqueous Media

“…As a result, the IL immobilized catalyst is regenerated and can be used for further reactions. Water is known to be the cheapest, environmentally benign, safe and most abundant compound on the earth's surface; and it has attracted a great deal of attention from a green chemistry perspective [33][34][35][36][37][38][39][40][41][42][43]. In addition, water also holds some unique physical and chemical properties, such as high surface tension, hydrogen bonding capability, high dielectric constant and high cohesive energy density [44][45][46].…”