20170-34-7Relevant academic research and scientific papers
Pd-Catalysed Suzuki coupling of α-bromoethenylphosphonates with organotrifluoroborates: A general protocol for the synthesis of terminal α-substituted vinylphosphonates
Zhang, Li,Fang, Yewen,Jin, Xiaoping,Xu, Housan,Li, Ruifeng,Wu, Hao,Chen, Bin,Zhu, Yiming,Yang, Yi,Tian, Zongming
supporting information, p. 8985 - 8989 (2017/11/09)
A general and robust protocol for the synthesis of terminal α-substituted vinylphosphonates via Suzuki coupling of α-bromovinylphosphonates with organotrifluoroborates has been successfully developed. This method features a broad substrate scope, great functional group compatibilities, and easy scale-up ability. In addition to easy access of nucleophiles, a straightforward synthesis of electrophiles was also realized with diethyl α-bromoethenylphosphonate as the starting material. With a combination of Pd2(dba)3/SPhos as the catalyst, a range of α-alkyl, aryl, heteroaryl, and alkynyl substituted ethenylphosphonates could be nicely accessed under mild conditions. As a synthetic application, the terminal vinylphosphonate was utilized as an effective Michael acceptor in the visible-light-promoted Giese reaction.
Total Synthesis of Anti-Influenza Agents Zanamivir and Zanaphosphor via Asymmetric Aza-Henry Reaction
Lin, Long-Zhi,Fang, Jim-Min
supporting information, p. 4400 - 4403 (2016/10/23)
The potent anti-influenza agents, zanamivir and its phosphonate congener, are synthesized by using a nitro group as the latent amino group at C4 for asymmetric aza-Henry reaction with a chiral sulfinylimine, which is derived from inexpensive d-glucono-?-lactone to establish the essential nitrogen-containing substituent at C5. This method provides an efficient way to construct the densely substituted dihydropyran core of zanamivir and zanaphosphor without using the hazardous azide reagent.
α-Phosphonovinyl Arylsulfonates: An Attractive Partner for the Synthesis of α-Substituted Vinylphosphonates through Palladium-Catalyzed Suzuki Reactions
Fang, Yewen,Zhang, Li,Jin, Xiaoping,Li, Jinjian,Yuan, Meijuan,Li, Ruifeng,Wang, Tong,Wang, Tao,Hu, Hanjun,Gu, Juejun
, p. 1577 - 1587 (2016/04/05)
It has been demonstrated that a variety of α-phosphonovinyl arylsulfonates with electron-neutral, -donating, and -withdrawing groups on the phenyl ring could be conveniently and efficiently prepared. In the presence of a Pd(OAc)2/SPhos-based catalyst, various organoboron compounds could be employed as the nucleophilic coupling partners, such as organoboronic acids, boronate esters, and organotrifluoroborates. The newly developed O-centered electrophiles could couple with a multitude of aryl, heteroaryl, and alkylboron reagents, to give α-substituted vinylphosphonates in moderate to excellent yields. Generally, the Suzuki reaction is tolerant of extensive substitution at the aromatic ring of both electrophilic and nucleophilic coupling partners. As in the case of the Suzuki reaction of 8-quinolineboronic acid, proper choice of α-phosphonovinyl arylsulfonates is critical to efficient coupling. Moreover, the prospect for application of this method to complex synthesis has been demonstrated through the coupling of estrone-derived arylborons. The present protocol also features mild conditions and high efficiency. A new and attractive coupling partner for the synthesis of α-substituted vinylphosphonates through Suzuki reactions has been developed. The developed O-centered electrophiles couple with various organoboron reagents to give α-substituted vinylphosphonates in moderate to excellent yields. This protocol features broad substrate scope, mild conditions, and high efficiency.
Microwave-assisted palladium-catalyzed cross-coupling of aryl and vinyl halides with H-phosphonate diesters
Kalek, Marcin,Ziadi, Asraa,Stawinski, Jacek
supporting information; experimental part, p. 4637 - 4640 (2009/05/26)
(Chemical Equation Presented) A general and efficient method for the microwave-assisted formation of the C-P bond was developed. Using a prevalent palladium catalyst, Pd(PPh3)4, a quantitative cross-coupling of various H-phosphonate diesters with aryl and vinyl halides was achieved in less than 10 min. The reactions occurred with retention of configuration at the phosphorus center and in the vinyl moiety. Using this protocol, several C-phosphonates, including those bearing nucleoside and cholesteryl moieties, were prepared in high yields.
A useful synthesis of diethyl 1-substituted vinylphosphonates
Krawczyk,Koszuk,Bodalski
, p. 1123 - 1128 (2007/10/03)
A variety of diethyl 1-substituted vinylphosphonates 8 has been conveniently synthesized by piperidine catalyzed decarboxylative condensation of 2-diethoxyphosphorylalkanoic acids and 2-diethoxyphosphorylalkenoic acids 7 with formaldehyde.
A convenient synthesis of α-substituted vinylphosphonates based on dithio-and selenophosphates
Maciagiewicz,Dybowski,Skowronska
, p. 2389 - 2393 (2007/10/03)
A convenient synthesis of α-substituted vinylphosphonates based on the reaction of readily available S-(β-oxoalkyl)dithiophosphates and Se-(β-oxoalkyl)selenophosphates with sodium dialkyl phosphites is described.
Synthesis of α- and γ-Fluoroalkylphosphonates
Blackburn, G. Michael,Kent, David E.
, p. 913 - 918 (2007/10/02)
α-Fluorobenzylphosphonate esters are conventiently made by treating α-hydroxybenzylphosphonate esters with diethylaminosulphur trifluoride.The reaction is not subject to steric impedance and is extended to the α-fluorination of an α-hydroxybenzylphosphine oxide.For α-hydroxyallyl and α-hydroxycinnamylphosphonates, the replacement of the hydroxy group by fluorine proceeds via an SN2' rearrangement to give γ-fluoroalk-1-enylphosphonates exclusively.Dehydration rather than substitution occurs in the case of alcohols of secondary alkylphosphonates.
Epoxydation catalitique de phosphonates α,β- et β,γ-ethyleniques a l'aide d'hydroperoxydes
Sturtz, Georges,Pondaven-Raphalen, Annick
, p. 125 - 130 (2007/10/02)
The α,β- and β,γ-unsaturated phosphonates can be epoxidized with two catalytic systems, hydrogen peroxide in the presence of sodium tungstate and t-butyl hydroperoxide in the presence of molybdenum hexacarbonyl.Whatever the conditions used, β,γ-unsaturated ones.The molybdenum/t-butyl hydroperoxide complex has been found to be the most effective epoxidising agent in the preparation of dialkyl 2,3-epoxy alkyl phosphonates.
Mesylate Derivatives of α-Hydroxy Phosphonates. Formation of Carbocations Adjacent to the Diethyl Phosphonate Group
Creary, Xavier,Geiger, Cristina C.,Hilton, Kathryn
, p. 2851 - 2858 (2007/10/02)
Mesylates 3-6 have been prepared and reacted in a variety of solvents.Product, rate, and solvent effect studies implicate carbocationic intermediates in these solvolyses despite the electron-withdrawing PO(OEt)2 group.Mesylate 3 gave exclusive substitution products.Optically active 3 gave racemic products on trifluoroacetolysis. α-Deuterium isotope effects were also in line with a cationic intermediate.Mesylate 4 gave some elimination product, 27, along with the substitution product 28, also via a cationic intermediate.Mesylates 5 and 6 gave exclusive elimination products.A β-deuterium isotope effect study gave a kH6/kD6 value of 2.8.This isotope effect, along with a small m value (0.45), suggested the intermediacy of a reversibly formed ion pair which subsequently loses a proton.This mechanism represents the merging of the classical E1 mechanism and the E2C(+) mechanism, the latter representing the cationic counterpart of the E1cb mechanism.Analysis of the solvolysis rates of 3 and 4 led to the conclusion that cationic intermediates are formed quite easily.Reasons are suggested for this unexpectedly facile generation of cations adjacent to the potent electron-withdrawing PO(OEt)2 substituent.
A NEW SYNTHETIC APPROACH TO α,β-UNSATURATED PHOSPHONATES (1-METHYLENEALKANE-PHOSPHONATES)
Inokawa, S.,Yamamoto, H.
, p. 79 - 82 (2007/10/02)
α,β-Unsaturated phosphonates were prepared in good yields by refluxing 1,2-epoxy-1-alkyl-ethanephosphonates in methanol with thiourea (5 equiv.) for 4 hours.
