19879-97-1Relevant academic research and scientific papers
Preparation method of tiglic aldehyde
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Paragraph 0036; 0037; 0041; 0044, (2020/03/05)
The invention discloses a preparation method of tiglic aldehyde. The preparation method disclosed by the invention comprises the following step: in a solvent, in the presence of a Lewis acid, carryingout Mukaiyama reaction shown in the specification on allyl silyl ether and trimeric acetaldehyde to obtain 3-hydroxy-2-methylbutyraldehyde shown in the formula I. The invention further discloses a preparation method of the 3-hydroxy-2-methylbutyraldehyde. The preparation method has the advantages that the raw materials are cheap and easy to obtain, the preparation operation of the intermediate issimple, the reaction conditions are mild, and large-scale production is easy.
New tetraphosphorus ligands for highly linear selective hydroformylation of allyl and vinyl derivatives
Cai, Chaoxian,Yu, Shichao,Cao, Bonan,Zhang, Xumu
experimental part, p. 9992 - 9998 (2012/09/07)
New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of functionalized allyl and vinyl derivatives. Remarkably high linear selectivity was obtained by these tetraphosphorus ligands. The ligand that bears strong electron-withdrawing 2,4-difluorophenyl groups is the most effective one in affording linear aldehydes. The Rh/tetraphosphorus ligand catalyst is highly effective to produce linear aldehydes from functionalized allyl derivatives with heteroatoms or aromatic groups directly adjacent to the allyl group. For vinyl derivatives, the ligand is highly linear selective for acrylic derivatives, styrene, vinyl pyridine, and vinyl phthalimide. Linear to branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of allyl and vinyl olefins (see scheme). Remarkably high linear selectivities were obtained by these ligands. Linear-to-branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. Copyright
Thermally stable, latent olefin metathesis catalysts
Thomas, Renee M.,Fedorov, Alexey,Keitz, Benjamin K.,Grubbs, Robert H.
scheme or table, p. 6713 - 6717 (2012/02/06)
Highly thermally stable N-aryl, N-alkyl N-heterocyclic carbene (NHC) ruthenium catalysts were designed and synthesized for latent olefin metathesis. These catalysts showed excellent latent behavior toward metathesis reactions, whereby the complexes were inactive at ambient temperature and initiated at elevated temperatures, a challenging property to achieve with second-generation catalysts. A sterically hindered N-tert-butyl substituent on the NHC ligand of the ruthenium complex was found to induce latent behavior toward cross-metathesis reactions, and exchange of the chloride ligands for iodide ligands was necessary to attain latent behavior during ring-opening metathesis polymerization (ROMP). Iodide-based catalysts showed no reactivity toward ROMP of norbornene-derived monomers at 25 °C and upon heating to 85 °C gave complete conversion of monomer to polymer in less than 2 h. All of the complexes were very stable to air, moisture, and elevated temperatures up to at least 90 °C and exhibited a long catalyst lifetime in solution at elevated temperatures.
Convenient synthesis of isoxazolines via tandem isomerization of allyl compounds to vinylic derivatives and 1,3-dipolar cycloaddition of nitrile oxides to the vinylic compounds
Krompiec, Stanis?aw,Bujak, Piotr,Szczepankiewicz, Wojciech
supporting information; experimental part, p. 6071 - 6074 (2009/04/11)
A novel effective method for the synthesis of new isoxazolines via tandem isomerization of QCH(X)CH{double bond, long}CH(Y) to QC(X){double bond, long}CHCH2(Y) (Q = RO, RS, R2N, R3Si, etc.; X = H, R, OR; Y = H, R; R = alkyl, aryl) catalyzed by ruthenium complexes and 1,3-dipolar cycloaddition of the latter compounds to arenenitrile oxides is presented. The cycloaddition of QCH(X)CH{double bond, long}CH(Y) to 2,6-dichlorobenzonitrile oxide is also described. The regio- and stereoselectivity of the cycloaddition of nitrile oxide to allyl and 1-propenyl (vinylic in general) compounds is discussed.
PREPARATION AND DIENOPHILICITY OF 3-METHYL-4,5-BENZOFURANDIONE
Lee, Junning,Tang, Jin,Snyder, John K.
, p. 3427 - 3430 (2007/10/02)
The o-quinone 3-methyl-4,5-benzofurandione, 1, was prepared in 94percent overall yield from p-benzoquinone and 1-morpholino-propene.The cycloaddition chemistry of 1 with several dienes was examined and found to proceed in good to excellent yields.
A NEW, EFFICIENT SYNTHESIS OF THE LEFT HALF OF NARASIN
Tino, Joseph A.,Lewis, Michael D.,Kishi, Yoshito
, p. 97 - 104 (2007/10/02)
The coupling of the acetates 15a,b or 17a,b with the enol silyl ether 19 in the presence of ZnCl2 was shown to yield exclusively the desired C.7 axial products.The stereoselectivity at the C.8 position was about 3.5:1 favoring the natural configuration.
Enol Ethers, XVII. Acylation of Trimethylsilyl Enol Ethers with Malonyl Dichloride - Synthesis of 4-Hydroxy-2H-pyran-2-ones
Effenberger, Franz,Ziegler, Thomas,Schoenwaelder, Karl-Heinz,Kesmarszky, Thomas,Bauer, Bernd
, p. 3394 - 3404 (2007/10/02)
Trimethylsilyl enol ethers of aldehydes 1, acyclic and cyclic ketones 4 and 10, respectively, are acylated by malonyl dichloride (2) at room temperature or even at -60 deg C.After aqueous workup, the 6-unsubstituted 4-hydroxy-2H-pyran-2-ones 3 are obtained from 1-(trimethylsiloxy)alkenes 1, whereas the 5,6-alkylene-bridged 4-hydroxy-2H-pyran-2-ones 11 are formed from 1-(trimethylsiloxy)cycloalkenes 10.Acylation of 2-(trimethylsiloxy)-1-propene (4a) and 3-(trimethylsiloxy)-2-pentene (4b) results in mixtures of 4-(trimethylsiloxy)-2H-pyran-2-ones 5 (main products) and phloroglucinol tris(trimethylsilyl) ethers (6) (by-products).
TOTAL SYNTHESIS OF (+/-)-THIOLACTOMYCIN
Wang, Chia-Lin J.,Salvino, J. M.
, p. 5243 - 5246 (2007/10/02)
We have completed the first total synthesis of (+/-)-thiolactomycin by a five-step procedure in 10percent overall yield starting from ketoester 6.The key step involves addition of dianion 3 to 3-ethoxy-2-methyl-2-propenal.The resulting aldehyde 11 was then converted into (+/-)-thiolactomycin.
