Micellar Solution of Sodium Dodecyl Sulfate (SDS) Catalyzes Kabacknik-Fields Reaction in Aqueous Media

Abstract

A new, convenient and high-yielding procedure for the one-pot synthesis of diethyl a-aminophosphonates from aldehydes, amines and diethyl phosphite (Kabacknik-Fields reaction) in SDS micellar solution in aqueous media is described. The synthesis of aaminophosphonates in the present study represents a three-component reaction in which no intermediate formation of either an imine or a-hydroxyphosphonate was observed.Use of aqueous media as a reaction solvent has attracted much attention in synthetic organic chemistry for several reasons. 1 In comparison with organic solvents, water is cheap, safe, reduces the use of harmful organic solvents and leads to the development of environmentally friendly chemical processes. 2 In addition, reactions in aqueous media illustrate unique reactivities and selectivities that are not usually observed in organic media. 3 However, organic solvents are still used instead of water for mainly two reasons. First, most organic substrates are not soluble in water and, as a result, water cannot function as a reaction medium. Second, many reactive substrates, reagents and catalysts are sensitive towards water and are decomposed or deactivated in aqueous media. A possible way to improve the solubility of substrates is the use of surfaceactive reagents that can form micelles 4 or vesicular structures in aqueous media. Micelles are dynamic clusters of surfactant molecules which posses both hydrophilic and hydrophobic structures. 5 It is well established that, in many cases, the rates and pathways of many chemical reactions can be altered by performing the reactions in micellar media instead of pure bulk solvents. Micelles can concentrate the reactants within a small volume, stabilize substrates, intermediates or products and orient substrates so that ionization potential, oxidation-reduction properties, dissociation constants, physical properties and reactivities are changed. Thus, they can alter the reaction rate, mechanism, regio-and stereoselectivity of the reaction. 6

Silica gel and polystyrene supported aluminum chloride as heterogeneous catalysts for the preparation of α‐aminophosphonates

“…Ketones also afforded the corresponding phosphates in relatively good yields (entries 25, 27). However, under the same reaction conditions the coupling reaction of ketones with aniline and diethyl phosphite in the presence of PS-AlCl 3 was very slow (entries 26,28). In another attempt, we extend the efficiency of the method by using different amines including different substituted anilines and primary aliphatic amines in the condensation with benzaldehyde and diethyl phosphite (entries 29-44).…”

“…Three-component condensation of an aldehyde, an amine, and a phosphite is the most convenient method for the preparation of these compounds. Several types of catalysts were introduced previously for this purpose, such as ZrCl 4 [11], AlCl 3 [12], LiClO 4 [13], SiO 2 -NH 4 HCO 3 [14], Al(OTf) 3 [15], ionic liquid [bmim]Cl-AlCl 3 [16], Mg(ClO 4 ) 2 [17], TiCl 4 [18], Al 2 O 3 -SbCl 3 [19], ZrOCl 2 ·8H 2 O [20], TiO 2 [21], amberlyst-15 [22], [Cu(3,4-tmtppa)](MeSO 4 ) 4 [23], sulfamic acid [24], FeCl 3 [25], sodium dodecyl sulfate [26], mesoporous aluminosilicate nanocage [27], and H 3 BO 3 [28]. Most of the above-mentioned methods suffer from the drawbacks such as generation of environmentally perilous waste material, tedious workup, long reaction times, the use of malodorous trialkyl phosphite as the phosphorus nucleophile, unsatisfactory yields, complicated operations, and the use of moisture-sensitive, expensive, hazardous, difficult to handle, or unreusable catalysts.…”

Recent Advances in H-Phosphonate Chemistry. Part 2. Synthesis of C-Phosphonate Derivatives

“…To overcome this problem, micellar solutions of surfactants were used as catalysts. Sobhani and Vafaee [29] reported on the efficient formation of α-aminophosphonates (yields >90%) from aldehydes, amines, and diethyl H-phosphonate in the presence of sodium dodecylsulfate (SDS, Fig. 1) in aqueous solution.…”

Facile synthesis of α‐amino phosphonates in water by Kabachnik–Fields reaction using magnesium dodecyl sulfate

“…Commercially available reagents were used without purification. The α-amino phosphonates 4a, [8] Magnesium dodecyl sulfate (1a): To a solution of sodium dodecyl sulfate (3.036 g, 10 mmol) in H 2 O (15 mL) was added MgBr 2 ·6H 2 O (1.411 g, 5 mmol) at room temperature. Viscous white precipitates appeared immediately, and the mixture was stirred for 2 h. The white lustrous solid was filtrated and dried (1 mmHg/15 h at room temperature).…”

“…• C was reported to give α-amino phosphonate [8]. In the presence of 0.1 equiv of MgSO 4 , the reaction proceeded to give 4a in 47% yield after 2.5 h (entry 8 …”