92975-72-9Relevant academic research and scientific papers
Organic-inorganic hybrid polymer-encapsulated magnetic nanobead catalysts
Arai, Takayoshi,Sato, Toru,Kanoh, Hirofumi,Kaneko, Katsumi,Oguma, Koichi,Yanagisawa, Akira
, p. 882 - 885 (2008/09/21)
A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic-inorganic hybrid polymer. The hybrid polymer of {[Cu-(bpy)(BF4)2(H2O) 2](bpy)}n (bpy = 4,4′-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding α-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic-inorganic hybrid-polymer-coated magnetic beads could be possible.
Chiral Carbanions, 1. - Configurational Stability and Reactions of α-Acyloxy-Substituted α-Methylbenzyllithium Compounds
Hammerschmidt, Friedrich,Hanninger, Achim
, p. 1069 - 1078 (2007/10/03)
Racemic and optically active 1-phenylethyl esters of pivalic, (-)-camphanic and 2,4,6-triisopropylbenzoic acid were prepared.The esters 7a of pivalic acid were deprotonated with lithium 2,2,6,6-tetramethylpiperidide (Li-TMP) to form α-oxy-α-methylbenzyllithium compounds which are partly configurationally stable prior to acylation with starting material.Camphanic ester (-)-7b cannot be deprotonated by Li-TMP and t-BuLi is added to the ester function to afford ketone (-)-12a. 1-Phenylethyl 2,4,6-triisopropylbenzoates 16 were transformed within minutes to carbanions 19 by using s-BuLi/TMEDA in THF, hexane, toluene and s-BuLi without TMEDA in toluene/20percent diethyl ether at -78 deg C.The carbanions are configurationally stable only in toluene/20percent diethyl ether and racemise partly in the other solvents.They react with a variety of electrophiles with either retention or inversion (Me3SnCl) of configuration.Carbanions 19 rearrange on warming to -20 deg C to hydroxy ketone 24 with racemisation. - Keywords: Esters, 1-phenylethyl; Carbanions, α-methyl-α-oxybenzyl, configurational stability; Ester-hydroxy ketone rearrangement
Improved method for samarium diiodide induced reductive coupling reactions of acid halides
Ruder, Suzanne M.
, p. 2621 - 2624 (2007/10/02)
Acid halides are known to be reductively coupled with aldehydes and ketones in the presence of samarium diiodide to generate α-hydroxy ketones. Low yields coupled product are obtained due to the competitive process of tetrahydrofuran attack on the acid chloride. This competitive reaction can be avoided and yields improved by preparation of samarium diiodide in acetonitrile.
REACTIONS OF ACYL ANIONS GENERATED FROM ACID CHLORIDES AND DIIODOSAMARIUM
Souppe, J.,Namy, J-L.,Kagan, H.B.
, p. 2869 - 2872 (2007/10/02)
Acid chlorides react with SmI2 to give α-diketones.Various experiments show that the initially formed acyl radical is rapidly transformed into an acyl anion which is thus generated by quite an unusual route.This species acylates acid chlorides, aldehydes and ketones in situ to give α-diketones and α-diketols.There are some limitations to this acyl anion chemistry but the reactions are realized with a good efficiency at room temperature in THF solution.
