AOT-Based Microemulsions Accelerate the 1,3-Cycloaddition of Benzonitrile Oxide to N-Ethylmaleimide

Abstract

We studied the 1,3-dipolar cycloaddition of benzonitrile oxide to N-ethylmaleimide in AOT/isooctane/water microemulsions at 25.0 degrees C and found the reaction rate to be roughly 150 and 35 times greater than that in isooctane and pure water, respectively. The accelerating effect of the microemulsion is the combined result of an increase in the local concentrations of the reactants through incorporation into the interface and of the intrinsic rate of the process through electrostatic interactions with the headgroups in the surfactant.

A molecular “screw-clamp”: accelerating click reactions in miniemulsions

“…The system studied herein uses a non-ionic surfactant, which avoids the interference of charges in the kinetics of the reaction, as observed by Engberts and coworkers for the kinetics of cycloadditions in microemulsions. 18 Thus, this system is a better comparison to solution polymerization. Two assumptions have been made for the application of the pseudo-phase model: (a) the distribution of the components is a thermodynamic equilibrium, which can be represented by the partition coefficient;…”

Partitioning of Hydrophobic Molecules to Liposome Membranes Can Induce Variations in their Micro-Polarity and Micro-Viscosity

“…The 1,3-dipolarcycloaddition reaction, one of the well-known Dields-Alder reactions, requires each reactant to have a high-diffusion coefficient within one phase in multiple phase systems, although most of the substrates are hydrophobic and are not readily dissolved in the water phase. In order to achieve such an organic synthesis in the water phase, the self-assembly systems, such as micelles, oil-in-water emulsions, and vesicles, have been studied to improve the yield and stereoselectivity [4][5][6]. Liposomes are self-assembled phospholipid bilayers in water, where the basic structure of a lipid membrane is the lipid bilayer with a 5 nm-thickness consisting of a polar membrane surface and a non-polar inner membrane [7].…”

Capture of 3‐Amino‐4‐oxycyanofurazan and Characterization of Isoxazole Product

“…Unfortunately, the procedure suffered from low yield of the last step. However, the mechanism was unproved, because AOCF was unstable even at low temperature and could not be isolated from the reaction system [13][14][15][16][17][18]. To our knowledge, only a primitive mechanism was reported, which proposed an intermediate, 3-amino-4-oxycyanofurazan (AOCF) [11,12], presenting before the formation of DATF (Scheme 2).…”

“…To our knowledge, only a primitive mechanism was reported, which proposed an intermediate, 3-amino-4-oxycyanofurazan (AOCF) [11,12], presenting before the formation of DATF (Scheme 2). However, the mechanism was unproved, because AOCF was unstable even at low temperature and could not be isolated from the reaction system [13][14][15][16][17][18].…”