Amino acids as suitable N-nucleophiles for the aza-Michael reaction of vinylphosphoryl compounds in water

Rare Earth Metal-Mediated Precision Polymerization of Vinylphosphonates and Conjugated Nitrogen-Containing Vinyl Monomers

“…Vinylphosphonates belong to one of the simplest and longest known phosphorus-containing monomers. Since the 1940s, several synthetic pathways for the synthesis of dialkyl vinylphosphonate (DAVP) monomers exist, and DAVPs are obtained in good yields from simple starting materials. , Among them, the Michaelis–Arbuzov reaction is commonly used to obtain ethyl or isopropyl substituted vinylphosphonate esters in a two-step reaction (Scheme a). − Aryl- and vinyl-substituted phosphonates can be synthesized in larger variety via palladium-catalyzed cross-coupling reactions from dialkyl phosphites (Scheme b). − Other reactions of vinylphosphonates, besides polymerization reactions, include Diels–Alder cyclization, thiol–ene click reaction, or 1,4-addition. − Recently, the coordination polymerization of vinylphosphonic acid (VPA) and diethyl vinylphosphonate (DEVP) for the synthesis of functionalized PE- co -PVPA and PE- co -PDEVP CdSe quantum dots has been published using phosphinesulfonato palladium catalysts tolerating a wide range of functional groups . The obtained molecular masses with low phosphorus incorporation were estimated from 1 H NMR spectra and found to be below 8 kDa for PE- co -PVPA.…”

Organocatalyzed synthesis of functionalized vinylphosphonates in water

“…Therefore, it may be concluded that the use of water as a solvent not only simplifies crude product isolation through freeze drying removal of water prior to chromatography, but also presumably increases the reaction kinetics. Indeed, it was shown recently that water markedly enhances the rate for aza Michael addition to vinylphosphonates . Since the formation of ammonium salt A and its further reaction with the nucleophile involve analogous reactions, one may expect a similar overall rate enhancement.…”

Aza‐Michael Reaction: A Decade Later – Is the Research Over?

“…Using organic bases such as tertiary amines in catalytic amounts (5-10 mol %) triggers the reaction. [73] When strongly nucleophilic cyclic secondary amines are refluxed for 6-10 h with crotonic, fumaric or maleic acids in water, aza-Michael adducts are isolated in 45-90 % yields. [74] When the same reactions are performed in the absence of water, corresponding amino acids are formed in low yields.…”

“…Such their reduced reactivity can be easily explained by the formation of zwitterionic species. Using organic bases such as tertiary amines in catalytic amounts (5–10 mol %) triggers the reaction [73] …”