185249-91-6Relevant articles and documents
Active Ruthenium (0) Nanoparticles Catalyzed Wittig-Type Olefination Reaction
Srivastava, Vivek
, p. 693 - 703 (2017/03/08)
Abstract: Five different Ru metal precursors were reduced in imidazolium based ionic liquids under hydrogen atmosphere (4?bar) at 50 °C to obtain well-dispersed and stable Ru nanoparticles. Transmission electron microscopy (TEM) analysis confirmed size of well dispersed ionic liquid mediated Ru particles (Ru NPs) of 5?nm (±0.5) in diameter. These ruthenium nanoparticles (in ionic liquids) were used for Wittig type olefination reaction under mild reaction environment (70 °C and 1?h). The corresponding stilbenes were obtained in good yield with low-average selectivity. The proposed methodology is especially efficient for the synthesis of stilbenes as they were synthesized in the absence of any additive (as a hydrogen acceptor). The new catalytic system was also successfully applied for the synthesis of polymethoxylated and polyhydroxylated stilbenes, including resveratrol and DMU-212. Graphical Abstract: [Figure not available: see fulltext.]
Ruthenium-catalyzed one-pot synthesis of (E)-(2-arylvinyl)boronates through an isomerization/cross-metathesis sequence from allyl-substituted aromatics
Hemelaere, Remy,Caijo, Frederic,Mauduit, Marc,Carreaux, Francois,Carboni, Bertrand
, p. 3328 - 3333 (2014/06/09)
We described the efficient preparation of (E)-(2-arylvinyl)boronates from allylbenzene derivatives on the basis of an isomerization/cross-metathesis sequence catalyzed by a modified Hoveyda-Grubbs catalyst. The implementation of the experimental procedure was simple and compatible with a large variety of substrates. This methodology provides a new chemical transformation not described to date. Allyl-substituted aromatics can thus be converted into diversely functionalized compounds, such as (E)-stilbene derivatives or (E)-vinyl azides, in only two steps. Copyright
Wittig-type olefination of alcohols promoted by nickel nanoparticles: Synthesis of polymethoxylated and polyhydroxylated stilbenes
Alonso, Francisco,Riente, Paola,Yus, Miguel
supporting information; experimental part, p. 6034 - 6042 (2010/02/28)
Nickel nanoparticles were found to promote the Wittig-type olefination of primary alcohols with phosphorus ylides. The latter can be prepared from the corresponding phosphonium salts with TiBuLi or in situ generated with lithium metal. The methodology is especially efficient for the synthesis of stilbenes and is applied in the absence of any additive as a hydrogen acceptor. A new approach, to the synthesis of polymethoxylated and polyhydroxylated stilbenes, including resveratrol, DMU-212 and analogues, is presented.
One-pot, fluoride-promoted wittig reaction
Fumagalli, Tiziano,Sello, Guido,Orsini, Fulvia
experimental part, p. 2178 - 2195 (2009/12/01)
A one-pot, fluoride-promoted Wittig reaction was developed. The reactions of ethyl -bromoacetate with aliphatic, aromatic, and heteroaromatic aldehydes in the presence of tri-n-butylphosphine and tetrabutylammonium fluoride produced ,-unsaturated esters in good to excellent yields and E-stereoselectivity. Under the same conditions, reactions of ethyl -bromopropionate, -bromo acetonitrile, and -bromoacetophenone with aliphatic and aromatic aldehydes in the presence of tri-n-butylphosphine and tetrabutylammonium fluoride produced the expected ,-unsaturated derivatives in good E-stereoselectivity. The protocol was extended to semistabilized ylides and applied to the synthesis of some combretastatin analogs.
One-pot hydrosilylation-protodesilylation of functionalized diarylalkynes: a highly selective access to Z-stilbenes. Application to the synthesis of combretastatin A-4
Giraud, Anne,Provot, Olivier,Hamzé, Abdallah,Brion, Jean-Daniel,Alami, Mouad
, p. 1107 - 1110 (2008/09/17)
An efficient stereoselective synthesis of Z-stilbenes has been developed from diarylalkynes via a new hydrosilylation-protodesilylation process. The scope and limitation of this method is presented to stereoselectively prepare a wide range of (Z)-stilbenes in a one-pot way is presented. A concise application to the preparation of combretastatin A-4 (CA-4), a vascular targeting agent inhibitor of tubulin polymerisation is described.
Novel resveratrol analogs
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Page 3, (2010/02/08)
This invention relates to novel resveratrol analogs of the formula given below; wherein R, R1, R2 and R3 are: 1. R=OH, R1=R2=R3=H; 2. R=OH, R1=Br, R2=R3=H;
Simple synthesis of 5-substituted resorcinols: A revisited family of interesting bioactive molecules
Alonso, Emma,Ramon, Diego J.,Yus, Miguel
, p. 417 - 421 (2007/10/03)
The reaction of 3,5-dimethoxybenzyl trimethylsilyl ether (3) with different aldehydes (n-PrCHO, n-C11H23CHO, MeCHO, PhCHO) in the presence of lithium powder and a catalytic amount of naphthalene (4 mol %) gave, after hydrolysis, the expected alcohols 4 in moderate yields. The dehydroxylation of these compounds through the corresponding mesylates 5 or directly from benzylic derivatives by catalytic hydrogenation, afforded compounds 6, which are finally demethylated to yield 5-alkyl-3,5-dihydroxyresorcinols, such as olivetol (7a), grevillol (7b), 1,3-dihydroxy-5-propylbenzene (7c), or dihydropinosilvine (7d). Dehydration of alcohol derivatives 4 followed by demethylation led to hydroxylated stilbene-type structures, such as pinosilvine (9d), resveratrol (9e), or piceatannol (9f), which in some cases can be hydrogenated to give saturated molecules such as combretastanin B-4 tetramethyl ether (6f) or chrysotobibenzyl (6g). Finally, when the naphthalene-catalyzed lithiation of compound 3 was performed in the presence of other electrophiles [Me3SiCl, t-BuCHO, CH3(CH2)4CHO, 4-Me3SiOC6H4CHO, (CH2)5CO, PhN = C = O, PhN = CHPh], the expected reaction products 12 were isolated, after hydrolysis.
