15958-02-8Relevant academic research and scientific papers
Hg/Pt-catalyzed conversion of bromo alkynamines/alkynols to saturated and unsaturated γ-butyrolactams/lactones via intramolecular electrophilic cyclization
Kumar, Yalla Kiran,Kumar, Gadi Ranjith,Reddy, Maddi Sridhar
, p. 1252 - 1260 (2016/02/03)
Convenient and general Hg(ii)/Pt(iv) catalyzed syntheses of γ-butyrolactams and α,β-unsaturated γ-butyrolactones/lactams are described via intramolecular electrophilic cyclizations of bromoalkynes with tosylamino and hydroxyl tethers. The reaction features the use of wet solvents, the exclusion of any base and additive, mild conditions and practical yields. We also synthesised few chiral lactams through this pathway. Additionally, it is shown that the NHTs group distanced further from the homopropargylic position assists regioselective bromoalkyne hydration to yield useful α-bromoketones. Furthermore, Boc protected bromo homo propargyl amines undergo 6-endo-dig cyclization through Boc oxygen to give bromomethylene substituted oxazinones.
Lewis base-catalyzed electrophilic lactonization of selenyl bromide resin and facile solid-phase synthesis of furan-2(5H)-one derivatives
Jun He, Rong,Chun Zhu, Bing,Wang, Yu Guang
, p. 523 - 528 (2014/07/07)
A facile solid-phase synthesis approach was developed for the rapid synthesis of multi-substituted furan-2(5H)-one derivatives libraries. The synthetic strategy included the selenyl bromide resin-induced electrophilic lactonization catalyzed by Lewis base, lithiation, nucleophilic substitution and oxidation-elimination of the selenium resins. The advantages of the new method are good yields, high purity, straightforward operations and high diversity of the products, lack of odor, and good stability of the selenium resins. Copyright
Efficient intramolecular cyclizations of phenoxyethynyl diols into multisubstituted α,β-unsaturated lactones
Egi, Masahiro,Ota, Yuya,Nishimura, Yuka,Shimizu, Kaori,Azechi, Kenji,Akai, Shuji
, p. 4150 - 4153 (2013/09/12)
AgOTf-catalyzed intramolecular cyclization of phenoxyethynyl diols proceeded under mild conditions to afford the multisubstituted α,β-unsaturated-γ-lactones in 55-98% yields. This method was also applicable to the synthesis of α,β-unsaturated-δ-lactones. A similar cyclization proceeded when AgOTf was replaced with a stoichiometric amount of N-bromosuccinimide to furnish the α-bromo-substituted α,β-unsaturated lactones.
Metal-free reductive cleavage of C-O σ-bonds in acyloin derivatives by an organic neutral super-electron-donor
Cutulic, Sylvain P. Y.,Findlay, Neil J.,Zhou, Sheng-Ze,Chrystal, Ewan J. T.,Murphy, John A.
supporting information; experimental part, p. 8713 - 8718 (2009/12/28)
(Chemical Equation Presented) Neutral organic electron-donor 7, formally a pyridinylidene carbene dimer, effects reductive cleavage of C-O σ-bonds in acyloin derivatives Ar(CO)CRR′OX (X = OAc, OPiv, OBz, OMs) and this represents the first cleavage of C-O σ-bonds by a neutral organic electron-donor. The methodology is applicable to a large array of substrates and the reduced counterparts were isolated in good to excellent yields. For certain substrates, donor 7 behaves as a base, effecting condensation reactions with some acetate ester derivatives of acyloins, leading to butenolides. The variation in reactivity among the different substrates was rationalized. 2009 American Chemical Society.
Sequential rhodium-catalyzed stereo- and regioselective addition of organoboron derivatives to the alkyl 4-hydroxy-2-alkynoates/lactonizaction reaction
Alfonsi, Maria,Arcadi, Antonio,Chiarini, Marco,Marinelli, Fabio
, p. 9510 - 9517 (2008/03/17)
(Chemical Equation Presented) The sequential rhodium-catalyzed addition/lactonization reaction of organoboron derivatives to alkyl 4-hydroxy-2-alkynoates would constitute a novel methodology for the synthesis of 4-aryl/heteroaryl/vinyl-2(5H)-furanones wit
THE PALLADIUM -TRIBUTYL FORMATE REAGENT IN THE STEREOSELECTIVE HYDROGENATION, AND STEREO- AND REGIOSELECTIVE HYDROARYLATION OF ALKYL 4-HYDROXY-2-ALKYNOATES: A ROUTE TO SUBSTITUTED BUTENOLIDES
Arcadi, A.,Bernocchi, E.,Burini, A.,Cacchi, S.,Marinelli, F.,Pietroni, B.
, p. 481 - 490 (2007/10/02)
The reaction of aryl iodides with alkyl 4-hydroxy-2-alkynoates in the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst provides a convenient route to functionalized substituted butenolides through a one pot hydroarylation/cyclization reaction.In the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst, alkyl 4-hydroxy-2-alkynoates undergo a one pot hydrogenation/cyclization reaction to the butenolide ring.By increasing the excess of formic acid, direct formation of saturated γ-lactones can be observed.Reaction occur with high stereoselectivity and, in the case of the hydroarylation, with goog regioselectivity.
Cycloaddition Reactions of Strained Ring Systems. Photochemistry of 1-Phenyl-2-carbomethoxy-3,3-dimethylcyclopropene
Padwa, Albert,Kennedy, G. Davon
, p. 4344 - 4352 (2007/10/02)
The sensitized irradiation of 1-phenyl-2-carbomethoxy-3,3-dimethylcyclopropene produced two novel photodimers.The minor product can be explained in terms of an initial bond formation to give a diradical intermediate.Collapse of the diradical furnishes a tricyclohexane which undergoes a subsequent cycloreversion to give a 1,4-cyclohexadiene derivative.The major photodimer is derived by cyclopropyl ring opening of the initially produced diradical followed by cyclization to give a bicyclobutane derivative.Direct irradiation of 1-phenyl-2-carbomethoxy-3,3-dimethylcyclopropene afforded a mixture of 1-carbomethoxy-3,3-dimethyl-1-phenylallene, 1-carbomethoxy-3-methyl-2-phenylbutadiene, and 2-carbomethoxy-3-methyl-1-phenylbutadiene.The formation of the three products can be rationalized in terms of a vinylcarbene intermediate which inserts into the adjacent methyl group.The product distribution favors cleavage of the carbomethoxy substituted ?-bond of the cyclopropene ring.This regioselectivity can be attributed to a funneling of the excited singlet state of the cyclopropene to the energy surface of the higher lying carbene state.The photochemical and thermal behavior of several hydroxyalkyl substituted cyclopropenes derived from 1-phenyl-2-carbomethoxy-3,3-dimethylcyclopropene was also studied and the results obtained were compared to the reactions in the carbomethoxy series.
HYDROXYDIHYDROFURANS. XX. STRUCTURE OF 2-HYDROXY-5,5-DIMETHYL-2-tert-BUTYL-4-PHENYL-(p-TOLYL)-2,5-DIHYDROFURANS
Yakovlev, S. V.,Serkova, V. I.,Pavlova, L. A.
, p. 1780 - 1782 (2007/10/02)
4-Phenyl- and 4-p-tolyl-2-hydroxy-5,5-dimethyl-2-tert-butyl-2,5-dihydrofurans exist in the cyclic form.When heated with dilute sulfuric acid, they are converted into the isomeric ethylenic γ-keto alcohols.After prolonged standing and when heated they are cleaved to form the corresponding butenolides.
