38453-85-9Relevant academic research and scientific papers
1H, 13C, 2D NMR and GCMS characterization of diol derivatives
Manivel,Khan, F. Nawaz
experimental part, p. 825 - 832 (2009/12/24)
Sodium borohydride (SBH) reduction of isocoumarins has been effected in presence of methanol to their respective diols. Diols have been isolated, purified and characterized by GCMS, proton, carbon and two-dimensional NMR spectroscopy analysis. Complete NMR assignments of diols are made using H-H COSY, as well as HSQC, HMQC and HMBC heteronuclear correlation techniques.
Lithiation reactions catalyzed by linear and cross-linked arene-based polymers. Generation of functionalized organolithium compounds
Candela,Gomez,Yus
, p. 795 - 801 (2007/10/03)
Lithiation of various substrates, such as chlorinated acetals, α-chloro ether, dichloro derivatives benzo-fused heterocycles, and allyl and benzyl derivatives, with excess lithium powder in the presence of a catalytic amount of soluble linear or insoluble cross-linked arene (naphthalene or biphenyl)-based polymers yields the expected organolithium intermediates. The latter react with electrophiles either in two steps or under Barbier-type reaction conditions to afford the corresponding adducts. The catalyst is easily recuperated by filtration at the end of the process, and the procedure can be regarded as a reasonable alternative to the use of free arenes as electron carrier in lithiation reactions.
Polyphenylene as an electron transfer catalyst in lithiation processes
Yus, Miguel,Gómez, Cecilia,Candela, Pablo
, p. 6207 - 6210 (2007/10/03)
The lithiation of different functionalised chlorinated materials (1a-c), dichlorinated compounds (1d-f) and benzofused cyclic ethers (1g,h) with lithium powder in the presence of catalytic amounts of either linear (LPP) or crosslinked (CPP) polyphenylene, in THF at temperatures ranging between -78 and 20°C, leads to the expected organolithium intermediates (Ia-h), which by reaction with electrophiles [ButCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe, Me3SiCl] gives, after hydrolysis with water, the expected products 2aa-hf.
Functionalised organotitanium compounds: From lithium to titanium intermediates in chemoselective reactions with carbonyl compounds
Pastor, Isidro M,Yus, Miguel
, p. 2365 - 2370 (2007/10/03)
The reaction of functionalised organolithium compounds 1 with an equimolecular mixture of two carbonyl compounds in the presence of 2 equiv. of triisopropoxytitanium chloride can discriminate between aldehyde and ketone, the process being selective for al
Electron-transfer-induced reductive cleavage of phthalans: Reactivity and synthetic applications
Azzena, Ugo,Demartis, Salvatore,Melloni, Giovanni
, p. 4913 - 4919 (2007/10/03)
The behavior of phthalan (1a) was investigated under conditions of electron transfer from alkali metals in aprotic solvents. Reaction with lithium in the presence of a catalytic amount of naphthalene in THF led to the reductive cleavage of an arylmethyl carbon-oxygen bond, with formation of a stable dilithium compound. Trapping of this intermediate with several electrophiles (alkyl halides, carbonyl derivatives, CO2) was successful. The extension of this procedure to several substituted phthalans (1b-i) was investigated, and the regiochemistry as well as the synthetic usefulness of these reactions are discussed.
1,2-Di(lithiomethyl)benzene from Phthalan: Sequential Introduction of Two Different Electrophiles
Almena, Juan,Foubelo, Francisco,Yus, Miguel
, p. 3351 - 3364 (2007/10/02)
The reaction of phthalan (1) with an excess of lithium powder and a catalytic amount of DTBB (2.5 mol percent) in THF at 20 deg C followed by treatment with electrophiles (D2O, CO2 and carbonyl compounds) at -78 deg C leads, after hydrolysis, to the corresponding functionalised benzylic alcohols 3a-g.When the lithiation reaction is continued, after the reaction with the first electrophile, and a second electrophile (H2O, D2O and carbonyl compounds) is added, the corresponding disubstituted compounds 6a-q are prepared.Diols 3c-g and 6h,i,l,n and hydroxyacids 6a,c,f,k are easily dehydrated to the corresponding cyclic ethers (7c-f, 8h,i,l,n) or lactones (9a,c,f,k) respectively.Finally, alcohols 6b,d,e give, after acid treatment, the Friedel-Crafts type benzocyclopentenes 10b,d,e.
Reductive electrophilic substitution of phthalans and ring expansion to isochroman derivatives
Azzena, Ugo,Demartis, Salvatore,Fiori, Maria Giovanna,Melloni, Giovanni,Pisano, Luisa
, p. 8123 - 8126 (2007/10/02)
Reductive cleavage of phthalan, 1a, with Li metal in the presence of a catalytic amount of naphthalene leads to the formation of a stable aromatic dilithium compound. The adducts of the latter with CO2, aldehydes or ketones undergo ring closure to isochroman derivatives, leading to ring expansion of the original heterocycle. The reductive electrophilic substitution procedure was successfully extended to the substituted phthalans 1b and 1c, to afford the corresponding isochroman-3-ones in satisfactory yields.
SEITENKETTENMETALLIERUNG 2-METHYLSUBSTITUIERTER BENZYLALKOHOLE
Braun, Manfred,Ringer, Ernst
, p. 1233 - 1234 (2007/10/02)
Treatment of the benzyl alcohols 1, 5a, and 7 with two equivalents of n-butyllithium gives the intermediates 2,6, and 8.By reaction with various electrophiles, the products 3a-c, 4a,b and 5b,c are formed.
