2653-90-9Relevant academic research and scientific papers
Alkene homologation: via visible light promoted hydrophosphination using triphenylphosphonium triflate
Levin, Vitalij V.,Dilman, Alexander D.
supporting information, p. 749 - 752 (2021/02/03)
A hydrophosphination reaction of alkenes with triphenylphosphonium triflate under photocatalytic conditions is described. The reaction is promoted by naphthalene-fused N-acylbenzimidazole and is believed to proceed through intermediate formation of a phosphinyl radical cation. The resulting phosphonium salts are directly involved in the Wittig reaction leading to homologated alkenes.
Synthesis of Denosomin-Vitamin D3 Hybrids and Evaluation of Their Anti-Alzheimer's Disease Activities
Sugimoto, Kenji,Yajima, Hisanari,Hayashi, Yusuke,Minato, Daishiro,Terasaki, Sayuri,Tohda, Chihiro,Matsuya, Yuji
supporting information, p. 5910 - 5913 (2015/12/11)
As an extension of previously conducted studies on developing an anti-Alzheimer's disease agent, denosomin (1-deoxy-24-norsominone, an artificial inducer of neurite elongation), derivatives were designed and synthesized based on the hypothesis that our denosomin would exhibit axonal extension activity via a 1,25D3-membrane-associated, rapid response steroid-binding protein (1,25D3-MARRS) pathway. The biological assay revealed that the hybridization of characteristic δ-lactone in denosomin and the triene moiety in VD3 was effective to enhance the nerve re-extension activity in amyloid β (Aβ)-damaged neurons.
Facile Pd(II)- and Ni(II)-catalyzed isomerization of terminal alkenes into 2-alkenes
Hwan, Jung Lim,Smith, Craig R.,RajanBabu
experimental part, p. 4565 - 4572 (2009/10/02)
(Chemical Equation Presented) Mono- and 2,2′-disubstituted terminal alkenes can be isomerized into the more stable internal (Z)- and (E)-alkenes by treating them with catalytic amounts of [(allyl)PdCl]2 or [(allyl)NiBr]2, a triarylph
The Sharpless asymmetric aminohydroxylation reaction: Optimising ligand/substrate control of regioselectivity for the synthesis of 3- and 4-aminosugars
Bodkin, Jennifer A.,Bacskay, George B.,McLeod, Malcolm D.
supporting information; experimental part, p. 2544 - 2553 (2009/02/02)
An investigation of the factors responsible for the sense and magnitude of regioselectivity in the Sharpless asymmetric aminohydroxylation (AA) has been conducted. Theoretical investigations of ligand-osmium binding geometry and experimental investigation
Total synthesis of (-)-allosecurinine
Leduc, Andrew B.,Kerr, Michael A.
scheme or table, p. 7945 - 7948 (2009/05/07)
(Chemical Equation Presented) Safe and secure: An efficient methodology which provides access to homochiral 2,5-cis pyrrolidines in excellent yields starting from chiral alkoxyamine cyclopropanes was used in the total synthesis of (-)-allosecurinine (see
Ru(III)-Catalyzed Cyclization of Arene-Alkene Substrates via Intramolecular Electrophilic Hydroarylation
Youn, So Won,Pastine, Stefan J.,Sames, Dalibor
, p. 581 - 584 (2007/10/03)
(Matrix presented) We herein report that RuCl3/AgOTf has proven to be a hydroarylation catalyst with an efficiency and scope superior to previously known methods. This catalyst demonstrated consistent performance with arene-ene substrates of diverse structural features, providing good to excellent yields of cyclization products (chromanes, tetralins, terpenoids, dihydrocoumarins).
Substituent effects on the rate constants for the photo-claisen rearrangement of allyl aryl ethers
Pincock, Alexandra L.,Pincock, James A.,Stefanova, Roumiana
, p. 9768 - 9778 (2007/10/03)
The photochemistry of 11 substituted allyl 4-X- and 3-X-aryl ethers 3 (ArOCH2-CH=CH2) has been examined in both methanol and cyclohexane as solvents. The ethers react by the photo-Claisen rearrangement to give allyl substituted phenols as the major primary photoproducts, as expected from the well-established radical pair mechanism. The excited singlet state properties (absorption spectra, fluorescence spectra, fluorescence quantum yields, and singlet lifetimes) were compared with a parallel set of unreactive 4-X- and 3-X-anisoles 4. The excited-state properties of three substituted 4-X-aryl 4-(1-butenyl) ethers 14 (ArOCH2CH2-CH=CH2) were also examined. The model compounds 4 and the reactive allyl ethers 3 have essentially identical rate constants for the excited-state processes with the exception of khoms, the rate constant for homolytic cleavage from S1 of the allyl ethers to give the radical pair. The difference between the fluorescence quantum yields and/or singlet lifetimes for 3 and 4 were used to obtain values of khoms for all of the allyl ethers. These values exhibit a large substituent effect, spanning almost 2 orders of magnitude with electron-donating groups (CH3O, CH3) accelerating the reaction and electron-withdrawing ones (CN, CF3) slowing it down. The parallel range of rate constants observed in both methanol and cyclohexane indicates that ion pairs are not important intermediates in these rearrangements. Quantum yields of reaction (Φr) for several of the more reactive ethers demonstrate that neither these values nor rate constants of reaction (khomr) derived from them are reliable measures of the actual excited-state process. In fact, the khomr values are significantly lower than the khoms ones, indicating that the radical pairs undergo recombination to generate starting material. Finally, the khoms rate constants were found to parallel a trend for the change in bond dissociation energy (ΔBDE) for the O-C (allyl) bond of the allyl ethers, indicating that other possible substituent effects are of minor importance.
The application of a mechanistic model leads to the extension of the sharpless asymmetric dihydroxylation to allylic 4-methoxybenzoates and conformationally related amine and homoallylic alcohol derivatives
Corey,Guzman-Perez, Angel,Noe, Mark C.
, p. 10805 - 10816 (2007/10/03)
The scope and utility of the Sharpless asymmetric dihydroxylation has been expanded to include the use of allylic 4-methoxybenzoates as precursors of a wide variety of substituted chiral glycerol derivatives. The allylic 4-methoxybenzoyl group was found to be superior to other allylic alcohol protecting groups with respect to both yield and enantiomeric purity of the product. For example, asymmetric dihydroxylation of allyl 4-methoxybenzoate (6a) using the (DHQD)2PYDZ·OsO4 (1·OsO4) catalyst system affords (S)-3-(4-methoxybenzoyloxy)-1,2-propanediol (7a) in >99% yield and 98% ee. The 4-methoxybenzoates of a variety of other allylic alcohols also serve as excellent substrates, in contrast to the parent alcohols themselves. The efficient asymmetric dihydroxylation of homoallylic 4-methoxyphenyl ethers (12a and 15), allyl 9-fluorenimine (18b), bis(homoallyl) 4-methoxybenzoate (14) and other structurally related substrates is also described. This methodology was developed under mechanistic guidance from the transition state model advanced earlier by us for the bis-cinchona alkaloid catalyzed asymmetric dihydroxylation reaction. The 4-methoxybenzoyl group functions not only to selectively protect one of the hydroxy groups of the product triol for subsequent synthetic manipulation but also to provide an extended binding group that participates in hydrophobic and aryl-aryl interactions with the U-shaped binding pocket of the (DHQD)2PYDZ·OsO4 catalyst (1·OsO4), thereby enhancing enantioselectivity.
Synthesis of 4-pyridines and 4--2,2'-bipyridines
Wang, Jiaxiong,Pappalardo, Maria,Keene, F. Richard
, p. 1425 - 1436 (2007/10/02)
The synthesis is reported of 4-pyridine (2), 4--2,2'-bipyridine (3) and 4-methyl-4'--2,2'-bipyridine (4), where the length of the alkyl chain is varied (n = 2, 5, 7, 9, 11).The synthetic methodology involved the reaction of the 3-(ω-bromoalkyl)thiophene with the anions derived from 4-methylpyridine, 4-methyl-2,2'-bipyridine or 4,4'-dimethyl-2,2'-bipyridine by lithiation.The n.m.r. (1H and 13C) and electronic spectral characteristics of the compounds are discussed.
