80997-79-1Relevant academic research and scientific papers
Synthesis of η3-2-stannylmethylallylpalladium complexes and their destannylation leading to trimethylenemethane-palladium species
Watanabe, Saisuke,Ogoshi, Sensuke,Kakiuchi, Kiyomi,Kurosawa, Hideo
, p. 19 - 26 (1994)
η3-2-Stannylmethylallylpalladium chloride dimer 3-CH2C(CH2SnMe3)CH2)Cl>2 (1a) reacted with a neutral ligand L to form corresponding cationic complexes 3-CH2C(CH2SnMe3)CH2)L2>Cl (L=PPh3: 2a, 1/2 bipy: 5 (bipy=2,2'-bipyridyl)), which were characterized by 1H NMR at low temperature only for 2a and at room temperature for 5.On addition of Bu3SnCl the cationic complex 5 underwent stannyl group exchange equilibrium with 3-CH2C(CH2SnBu3)CH2) (bipy)>Cl.Addition of 2 equiv PPh3 and RCHO (R=Ph, CH2=CH) to 1a at room temperature afforded the cycloaddition products, methylenetetrahydrofurans, in good yields.The complex 1a reacted with PhCHO in the presence of bipy and dppe (dppe = 1,2-bis(diphenylphosphino)ethane) to give the aldehyde adduct complexes 3-CH2C(CH2CHPh(OSnMe3))CH2)L2>Cl (L=1/2 bipy, 1/2 dppe), which were characterized by 1H NMR.The possible generation and the reactivities of the trimethylenemethane-palladium complex intermediate are discussed in the light of these results.Key words: Palladium; Stannyl; Destannylation; Trimethylenemethane
A new Ru catalyst for alkene-alkyne coupling
Trost, Barry M.,Toste, F. Dean
, p. 7739 - 7743 (1999)
[CpRu(CH3CN3)]+PF6- proves to be an effective catalyst for an intermolecular Alder ene type reaction that provides considerable broadening of scope of the process.
Novel synthesis of methylenecyclobutanols and 4-methylenetetrahydrofurans from γ-oxide ylides
Okuma, Kentaro,Kamahori, Yoshihiro,Tsubakihara, Kimiko,Yoshihara, Kanami,Tanaka, Yuichiro,Shioji, Kosei
, p. 7355 - 7360 (2007/10/03)
The reaction of δ-halo-γ-oxide ylide, prepared from methylenetriphenylphosphorane and epichlorohydrin, with aldehydes afforded alkylidenecyclobutanols in moderate yields. The reaction initially proceeded through internal nucleophilic attack on δ-carbon of this ylide. Another novel approach toward the synthesis of 4-methylenetetrahydrofurans was achieved by the reaction of γ-oxide ylides with paraformaldehyde.
Tetrahydrofuran derivatives from epoxides via group transfer cyclization or reductive radical cyclization of organotellurium and organoselenium intermediates
Engman, Lars,Gupta, Vijay
, p. 157 - 173 (2007/10/03)
Monosubstituted epoxides were regiospecifically ring-opened from the sterically least hindered side by benzenetellurolate and benzeneselenolate reagents to afford aryl β-hydroxyalkyl tellurides and selenides, respectively. These materials were O-allylated by treatment with allylic bromides/sodium hydride in tetrahydrofuran and O-prop-2-ynylated when reacted with propargyl bromide/sodium hydride. On photolysis in benzene containing 40 mol % of hexabutylditin, the β-(allyloxy)alkyl aryl tellurides were found to undergo group transfer cyclization to afford 2-substituted 4-[(aryltelluro)methyl]tetrahydrofurans (cis/trans = 1/3-1/10). The aryl β-(prop-2-ynyloxy)alkyl tellurides similarly afforded 2-substituted 4-[(aryltelluro)methylene]tetrahydrofurans with an E/Z-ratio close to unity. The β-(allyloxy)alkyl aryl selenides and aryl β-(prop-2-ynyloxy)alkyl selenides failed to undergo group transfer cyclization. In the presence of tributyltin hydride and 2,2'-azobisisobutyronitrile, the former compounds were found to undergo reductive radical cyclization in high yields to afford 2-substituted 4-methyltetrahydrofurans (cis/trans = 1/3-1/10). Aryl β-(prop-2-ynyloxy)alkyl selenides similarly afforded 2-substituted 4-methylenetetrahydrofurans. 2-Alkoxy-2-(allyloxy)ethyl phenyl selenides, prepared by allyloxyselenenation of vinyl ethers, were found to undergo reductive radical cyclization to afford 2-alkoxy-4-methyltetrahydrofurans (cis/trans = 13-1/4). The preference for formation of trans-2,4-disubstituted tetrahydrofurans in the group transfer and reductive radical cyclizations was rationalized assuming a chairlike transition state with a preferred adoption of a pseudoequatorial position of the 2-substituent. By carrying out the reactions at lower temperatures (ambient or -45°C), using triethylborane as an initiator, it was possible to further increase the trans selectivity in the reductive cyclizations.
Tributyltin chloride-sodium cyanoborohydride mediated tandem radical cyclisation-reductive demethoxylation sequence
Srikrishna,Viswajanani,Yelamaggad
, p. 10479 - 10488 (2007/10/03)
Reaction of the bromoketals 3, 7a-g and 11 with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of a catalytic amount of AIBN furnished the ethers 5, 8a-g and 13 via a tandem sequence comprising of a radical cyclisation reaction and tri-n-butylhalostannane and sodium cyanoborohydride mediated reductive demethoxylation of the resulting cyclic ketals.
3-Methylseleno-2-[methylselenomethyl]-propene valuable precursor of trimethylenemethane and trimethylenemethane dianion
Krief, Alain,Dumont, Willy
, p. 657 - 660 (2007/10/03)
3-Methylseleno-2-[methylselenomethyl]-propene proved to be a valuable precursor of 3-lithio-2-[methylselanomethyl]-propene and 3-lithio-2-[lithiomethyl]-propene. These have been reacted with various electrophiles and have in turn been successfully transfo
A novel and convenient synthesis of 2-aryl-4-methylenetetrahydrofurans from 2-(trimethylsiloxymethyl)allyltrimethylsilane and acetals
Oriyama,Ishiwata,Sano,Matsuda,Takahashi,Koga
, p. 5581 - 5584 (2007/10/03)
The reaction of acetals with 2-(trimethylsiloxymethyl)allyltrimethylsilane under the influence of the combined use of a catalytic amount of tin(II) halide and acetyl halide affords the corresponding 2-aryl-4-methylenetetrahydrofurans in good yields.
3-Methylenetetrahydrofurans and 3-Methylenepyrrolidines by Addition of 2-(Bromozincmethyl)-2-alkenyl Ethers or 2-(Chloromagnesiomethyl)-2-alkenyl Ethers to Aldehydes, Ketones and Imines followed by Pd(0)-Catalyzed Cyclization
Louw, Jaap van der,Baan, Juul L. van der,Stichter, Henk,Out, Gerardus J. J.,Kanter, Franciscus J. J. de,et al.
, p. 9877 - 9900 (2007/10/02)
Reaction of 2-(bromozincmethyl)-2-alkenyl ethers 1 or 2-(chloromagnesiomethyl)-2-alkenyl ethers 2 with aldehydes, ketones and imines affords the addition products 4 and 8, which undergo Pd(0)-catalyzed cyclization to the 3-methylenetetrahydrofurans 6 (Rs
3-METHYLENETETRAHYDROFURANS AND 3-METHYLENEPYRROLIDINES BY ADDITION OF 2-BROMOZINCMETHYL-2-PROPENYL ETHERS TO ALDEHYDES, KETONES AND IMINES FOLLOWED BY Pd(0)-CATALYZED CYCLIZATION
Louw, J. van der,Baan, J. L. van der,Stichter, H.,Out, G. J. J.,Bickelhaupt, F.,Klumpp, G. W.
, p. 3579 - 3580 (2007/10/02)
Reaction of 2-(benzyloxymethyl)- and 2-(phenoxymethyl)allylzinc bromides 1a and 1b with aldehydes, ketones and imines afforded the addition products 3 and 6, which underwent Pd(0)-catalyzed cyclization to the tetrahydrofurans 4 and pyrrolidines 7.
