Diethyl Vinylphosphonate

(A)The most commonly exploited reactions performed with 1 are Michael-type additions. These reactions can be applied in the synthesis of alkyl or aryl phosphonic amino esters, including cyclic ones. The reaction can be carried out in water2a,b or ionic liquids,2c in line with the trends of contemporary green chemistry (chemical equations presented).; (B) Michael reactions, 1,4-additions of carbanions, lead to the formation of C-C bonds. For example, deprotonation of highly CHacidic monofluorinated phosphonates, followed by addition to the 1, yields substituted terminal bisphosphonates. (chemical equations presented).; (C) Diethyl vinylphosphonate (1) can be also be applied as a vinylogous reagent in Heck-type coupling reactions. Diverse substituted mono- and polycyclic aromatic halides were treated with 1 in the presence of palladium catalysts. The yield of the reaction strongly depends on the type of the base used and varies for different aryl halides. (chemical equations presented).; (D) If an appropriate aromatic substrate is used, the palladium-catalyzed olefination can be followed by cyclization. Phosphonic, polycyclic derivatives of piperazine were prepared by this sequence. (chemical equations presented).; (E) Xiao and co-workers reported an interesting example of a cascade coupling using 1 and a substituted acetylene, forming a product with a conjugated system of double bonds. This cotrimerization was carried out under nickel catalysis. (chemical equations presented).; (F) The double bond of 1 can be exploited in ruthenium-mediated cross-metathesis reactions. Recently, it was applied in the synthesis of novel acyclic nucleoside phosphonates, structurally similar to known bioactive compounds, such as cidofovir. (chemical equations presented).; (G) Cycloaddition of diethyl vinylphosphonate (1) with carboxylic or phosphonic iminoesters afforded 3-phosphonylated 2,5-disubstituted pyrrolidines. The reaction was carried out in the presence of a chiral silver catalyst and with high enantio- and diastereoselectivity. (chemical equations presented).; (H) Deprotonated 1 can react with carbodiimides. In the cyclized product, one of the C=N bonds and the C=C bond of 1 remained intact. The product contains a nitrogen atom and a phosphorus atom in the ring. (chemical equations presented).; (I) Electrophilic addition of a trifluoromethyl group was performed on substrate 1 using the Togni Reagent II. Subsequent addition of trimethylsilyl azide, followed by workup, yielded 1-azido-3,3,3-trifluoropropylphosphonate. (chemical equations presented).; (J) Radical addition of carboradicals derived from halides was also performed with 1. Phosphonic derivatives of monosaccharides were synthesized in the presence of a ruthenium catalyst under irradiation with light. (chemical equations presented). © Georg Thieme Verlag Stuttgart New York.