149794-30-9Relevant academic research and scientific papers
α-ketophosphonates as ester surrogates: Isothiourea-catalyzed asymmetric diester and lactone synthesis
Smith, Siobhan R.,Leckie, Stuart M.,Holmes, Reuben,Douglas, James,Fallan, Charlene,Shapland, Peter,Pryde, David,Slawin, Alexandra M. Z.,Smith, Andrew D.
supporting information, p. 2506 - 2509 (2014/05/20)
Isothiourea HBTM-2.1 catalyzes the asymmetric Michael addition/ lactonization of aryl- and alkenylacetic acids using α-keto-β, γ-unsaturated phosphonates as α,β-unsaturated ester surrogates, giving access to a diverse range of stereodefined lactones or enantioenriched functionalized diesters upon ring-opening.
Organocatalytic access to enantioenriched dihydropyran phosphonates via an inverse-electron-demand hetero-Diels-Alder reaction
Weise, Christian F.,Lauridsen, Vibeke H.,Rambo, Raoní S.,Iversen, Eva H.,Olsen, Marie-Luise,J?rgensen, Karl Anker
, p. 3537 - 3546 (2014/05/06)
The enantioselective inverse-electron-demand hetero-Diels-Alder reaction of the remote olefin functionality in dienamines has been developed by the simultaneous activation of α,β-unsaturated aldehydes and acyl phosphonates. The dual activation is based on an organocatalyst that activates both the α,β-unsaturated aldehyde, through dienamine formation, and the acyl phosphonate by hydrogen-bonding. The enantioselective reaction results in the formation of dihydropyran frameworks with three contiguous stereogenic centers. Different substitution patterns are possible for both the heterodiene and the dienophile, and the target products are obtained in good yields and up to 92% ee. The potential of the reaction is demonstrated by transformation of the products into valuable and complex synthons.
Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates
Leckie, Stuart M.,Fallan, Charlene,Taylor, James E.,Brown, T. Bruce,Pryde, David,Lébl, Tomá?,Slawin, Alexandra M. Z.,Smith, Andrew D.
supporting information, p. 1243 - 1249 (2013/07/25)
NHC-mediated enantioselective formal [4+2] cycloadditions of alkylarylketenes with γ-substituted-β,γ-unsaturated α-ketophosphonates is described. A substrate-dependent switch in diastereoselectivity was observed, with γ-aryl α-ketophosphonates providing p
Enantioselective Friedel-Crafts alkylation reaction of indoles with α,β-unsaturated acyl phosphonates catalyzed by chiral phosphoric acid
Bachu, Prabhakar,Akiyama, Takahiko
supporting information; experimental part, p. 4112 - 4114 (2010/08/19)
A variety of indoles underwent enantioselective Friedel-Crafts alkylation with α,β-unsaturated acyl phosphonates in the presence of 10 mol% chiral BINOL-based phosphoric acid and subsequent treatment with methanol and DBU to give methyl 3-(indol-3-yl)prop
Enantioselective indole Friedel-Crafts alkylations catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes
Evans, David A.,Scheidt, Karl A.,Fandrick, Keith R.,Lam, Hon Wai,Wu, Jimmy
, p. 10780 - 10781 (2007/10/03)
A highly enantioselective Friedel-Crafts alkylation of electron-rich aromatic nucleophiles catalyzed by scandium(III) triflate-pyridyl(bis)oxazoline complexes has been accomplished. The reaction involves α,β-unsaturated acyl phosphonates as electrophiles and primarily substituted indoles as nucleophiles. The reactive acyl phosphonate product is converted to the corresponding ester or amide in good overall yield by adding an alcohol or amine directly to the reaction mixture. Copyright
Enantioselective synthesis of dihydropyrans. Catalysis of hetero Diels - Alder reactions by bis(oxazoline) copper(II) complexes
Evans, David A.,Johnson, Jeffrey S.,Olhava, Edward J.
, p. 1635 - 1649 (2007/10/03)
C2-symmetric bis(oxazoline) - Cu(II) complexes 1 and 2 catalyze the inverse electron demand hetero Diels - Alder reaction of α,β-unsaturated carbonyl compounds (heterodiene) with electron-rich olefins (heterodienophile) in high diastereo- and enantioselectivity, α,β- Unsaturated acyl phosphonates and β,γ-unsaturated α-keto esters and amides are effective heterodienes, while enol ethers and sulfides function as heterodienophiles. A range of substitution patterns is possible on the heterodiene: terminal alkyl, aryl, alkoxy, and thioether substituents are all tolerated. The enantioselective synthesis of dihydropyrans by this method has been shown to be straightforward: cycloadditions may be conducted with as little as 0.2 mol % of the chiral catalyst and are readily run on multigram scale. The reactions exhibit a favorable temperature - enantioselectivity profile, with selectivities exceeding 90% even at room temperature. A simple reaction protocol that employs a solid air-stable catalyst, convenient reaction temperatures, and low catalyst loadings is described. The utility of the derived cycloadducts in the preparation of chiral building blocks is demonstrated. Models for asymmetric induction are discussed considering product stereochemistry, X-ray crystallographic data for the solid catalysts, and mechanistic studies.
The preparation of acyl phosphonates by the heterogeneous oxidation of 1-hydroxy phosphonates
Liao, Yihua,Shabany, Hossein,Spilling, Christopher D.
, p. 8389 - 8392 (2007/10/03)
The oxidation of hydroxy phosphonates to acyl phosphonates using three heterogeneous systems, MnO2, KMnO4 and CrO2, was investigated. The best results were obtained with CrO2 in refluxing acetofinitrile.
