39491-72-0Relevant academic research and scientific papers
Divergent Reactivity of α,α-Disubstituted Alkenyl Hydrazones: Bench Stable Cyclopropylcarbinyl Equivalents
Ritchie, Nina F. C.,Zahara, Adam J.,Wilkerson-Hill, Sidney M.
supporting information, p. 2101 - 2106 (2022/02/14)
Herein we report the divergent reactivity of 2,2-dialkyl-3-(E)-alkenyl N-tosylhydrazones using Pd-catalyzed cross-coupling conditions, which enable the Z-selective synthesis of 3-aryl-1,4-dienes and gem-dialkyl vinylcyclopropanes. We found that the dialky
Nickel-Catalyzed system for the cross-coupling of alkenyl methyl ethers with grignard reagents under mild conditions
Hostier, Thomas,Neouchy, Zeina,Ferey, Vincent,Gomez Pardo, Domingo,Cossy, Janine
supporting information, p. 1815 - 1818 (2018/04/14)
A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, under mild conditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.
Bridging the final gap in stereocontrolled Wittig reactions: Methoxymethoxy-armed allylic phosphorus ylides affording conjugated dienes with high cis selectivity
Wang, Qian,El Khoury, Mirella,Schlosser, Manfred
, p. 420 - 426 (2007/10/03)
After treatment with an appropriate base (butyllithium or sodium amide), 2-alkenyltris(2-methoxymethoxyphenyl)phosphonium salts carrying an allyl, crotyl, or prenyl (3-methyl-2-butenyl) side chain condense with saturated or unsaturated aldehydes to give conjugated dienes with Z/E ratios ranging from 90:10 to >99:1 and averaging 96:4. Owing to steric congestion, yields are only moderate (on average 41%; extremes 10-79%). The nonvolatile tris(2- methoxymethoxyphenyl)phosphine oxide by-product can be readily isolated and reduced to recover the phosphane starting material, or it may be hydrolyzed to the water-soluble tris(2-hydroxyphenyl)phosphine oxide.
The simultaneous in-situ generation of aldehydes and phosphorus ylides: A convenient multi-step one-pot olefination protocol
Wang, Qian,Wei, Heng-Xu,Schlosser, Manfred
, p. 3263 - 3268 (2007/10/03)
The lithium α-(dimethylamino)alkoxides resulting from the nucleophilic addition of an organolithium reagent to N,N-dimethylformamide are basic enough to deprotonate alkyltriphenylphosphonium salts suspended in tetrahydrofuran. The aldehydes liberated by t
Regioselective 1,4-addition of ammonia to 1-arylalka-1,3-dienes and 1-aryl-4-phenylbuta-1,3-dienes by photoinduced electron transfer
Kojima, Ryuji,Yamashita, Toshiaki,Tanabe, Kimiko,Shiragami, Tsutomu,Yasuda, Masahide,Shima, Kensuke
, p. 217 - 222 (2007/10/03)
The photoamination of 1-arylalka-1,3-dienes 1a-f and 1-aryl-4-phenylbuta-1,3-dienes 1g-k with NH3 in the presence of p-dicyanobenzene (DCB) gives 4-amino-1-arylalk-2-enes 2a-f and 1-amino-1,4-diarylbut-2-enes 2g-k, respectively. The photoamination proceeds by nucleophilic addition of NH3 to the cation radicals of 1+. generated by photoinduced electron transfer to DCB. The regiochemistry of 2 is related to the distribution of the positive charge in 1+. calculated by the PM3-UHF/RHF method, the stability of the aminated radicals formed by the addition of NH3 to 1+. and the stability of the aminated anion formed by the reduction of the aminated radicals by DCB-.. The stabilities of these intermediates are estimated by the calculation of the heat of formation by the PM3-UHF/RHF method. Distributions of the positive charge in 1+. and the stabilities of the aminated anion show a good agreement with the product analysis.
Stereochemistry of the olefin formation from anti and syn heterocyclic β-hydroxy sulfones.
Baudin, J. B.,Hareau, G.,Julia, S. A.,Ruel, O.
, p. 336 - 357 (2007/10/02)
Reaction of aldehydes R2-CHO with the new lithio derivatives of 2-benzothiazoles or pyridines R1-CH2-SO2-Het afforded the corresponding β-hydroxy sulfones which are stable in the pyridine series and generally unstable in the benzothiazole series except for anti derivatives 10a and 20c. t-Butyl-dimethyl silyl ethers of all the heterocyclic β-hydroxy sulfones have been obtained by oxidation of the corresponding anti and syn sulfides, which have been stereoselectively prepared from the epoxides 17, 19, 21 and 23.The lithium or tetrabutylammonium alkoxides of heterocyclic β-hydroxy sulfones undergo an intramolecular addition to the neighboring C=N group followed by an S to O benzothiazole (or pyridine) transfer, and simultaneous extrusion of sulfur dioxide, ejection of benzothiazol-2(3H)-one anion and formation of the corresponding olefins.From the data of twenty cases studied, it can be concluded that the final elimination is entirely antiperiplanar only for the alkoxides of β-hydroxy-BT- or Pyr-sulfones anti or syn bearing saturated aliphatic chains R1 and R2 and for anti derivatives with R1 = R2 = C6H5.Due to their equilibration however, the alkoxides of numerous derivatives of heterocyclic (3-methylbut-2-enyl) or (phenylmethyl) sulfones do not follow entirely the above antiperiplanar elimination. Keywords: heteroaromatic sulfones / intramolecular ipso reaction / organolithium derivatives / stereochemistry / eliminations / olefination
Stereochemistry of direct olefin formation from carbonyl compounds and lithiated heterocyclic sulfones
Baudin, J. B.,Hareau, G.,Julia, S. A.,Lorne, R.,Ruel, O.
, p. 856 - 878 (2007/10/02)
The conditions for the title reaction were studied for the 2-benzothiazole and 2-pyridine series and for some examples in the 2-pyrimidine series.The olefin preparations were generally observed to be more efficient for 2-BT-sulfone systems.From the data of the hundred cases studied, it can be concluded that (E)-olefins are obtained: (i) from saturated BT-sulfones and aromatic aldehydes; and (ii) from benzylic BT-sulfones and branched saturated aldehydes (isobutyraldehyde, pivalaldehyde) or α,β-ethylenic or aromatic aldehydes. (Z)-olefins arise: (i) fom propargylic BT-sulfones and saturated or aromatic aldehydes; and (ii) from allylic or benzylic Pyr-sulfones and saturated aldehydes.Possible mechanisms for this new olefination procedure were examined. - heteroaromatic sulfones, organolithium derivatives, intramolecular ipso reactions, stereochemistry, elimination, olefination.
Stereoselective E and Z Olefin Formation by Wittig Olefination of Aldehydes with Allylic Phosphorus Ylides. Stereochemistry
Tamura, Rui,Saegusa, Koji,Kakihana, Masato,Oda, Daihei
, p. 2723 - 2728 (2007/10/02)
Sterically crowded allylic tributylphosphorus ylides such as β-γ-disubstituted allylic ylides react with various aldehydes to afford E olefins with high stereoselectivity (E>92percent).As the steric demand of the ylides was decreased, bulky aldehydes were required to achieve high E selectivity.On the other hand, predominant or exclusive formation of Z olefins was achieved by using allylic triphenylphosphorus ylides and tertiary aldehydes like pivaldehyde, while the combination of allylic triphenylphosphorus ylides and such large secondary aldehydes as cyclohexanecarboxaldehyde led to E olefin formation under the lithium salt free conditions.The distinct lithium salt effect was observed in the reaction effected with triphenylphosphorus ylides.The origin of the observed E or Z selectivity can be reasonably explained according to Vedejs' rationale on the Wittig reaction stereochemistry.
2-Allylisourea as a Starting Material for Palladium-Catalyzed Wittig-Type Allylidenation of Aldehydes
Inoue, Yoshio,Toyofuku, Masanori,Hashimoto, Harukichi
, p. 1279 - 1280 (2007/10/02)
2-Allylic-substituted isoureas underwent Wittig-type allylidenation of aldehydes in the presence of triphenylphosphine and 2 molpercent of to give the corresponding conjugated olefins in tolerable to good yields.
