55696-62-3Relevant academic research and scientific papers
Gold-catalysed cyclic ether formation from diols
Jiang, Xiaolu,London, Emma K.,Morris, David J.,Clarkson, Guy J.,Wills, Martin
experimental part, p. 9828 - 9834 (2011/02/23)
Gold(I) and (III) salts have been found to be highly effective at the catalysis of ether formation from alcohols. Intramolecular ether formation of a 1,5-diol was also achieved, with a stereoselectivity that indicates that an SN1 mechanism predominates. In an attempt to form a seven-membered ring, a stable 14-membered dimer product was also formed. Attempts to control the diastereoselectivity of the reaction using a chiral anionic counterion did not give products with a high de.
Efficient preparation of optically pure C2-symmetrical cyclic amines for chiral auxiliary
Sato, Mitsuo,Gunji, Yasuhiko,Ikeno, Taketo,Yamada, Tohru
, p. 1434 - 1438 (2007/10/03)
Optically pure C2-symmetrical amines were efficiently synthesized from the corresponding diols obtained from the enantioselective borohydride reduction of the diketones catalyzed by the optically active β-ketoiminato cobalt(II) complex.
Is it possible to estimate the enantioselectivity of a chiral catalyst from its racemic mixture?
Lagasse, Franz,Tsukamoto, Masaki,Welch, Christopher J.,Kagan, Henri B.
, p. 7490 - 7491 (2007/10/03)
The evaluation of a racemic catalyst was investigated in the case of oxazaborolidine (OAB)-catalyzed borane reduction of 1,5-diphenyl-1,5-pentanedione, giving the corresponding diol. On the basis of the diastereoselectivity of the diols, it is possible to estimate the enantioselectivity (ee) of the first step, which correlates well with the ee in the reaction of the structurally similar phenyl n-pentyl ketone with enantiopure OAB catalyst. The measure of diastereoselectivity could be a tool for screening racemic catalysts without the need for resolving the individual enantiomers, if in the second step of the process there is no substrate control and no catalyst scrambling. Copyright
Facile reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by an aqueous TiCl3/NH3 system: Selectivity and scope
Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
, p. 3326 - 3335 (2007/10/03)
A simple and rapid procedure for the almost quantitative reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by use of TiCl3/NH3 in aqueous methanol solution is reported. The reducing system distinguishes between different classes of aldehydes and/or ketones, and many functionalities that usually do not survive under reducing conditions are tolerated well. The concept of reversal of chemoselectivity has also been developed. A mechanism based on two sequential one-electron transfers from TiIII to the carbonyl carbon atom is proposed, the second SET becoming operative only in the presence of ammonium ion (either added or formed in situ). Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Design, synthesis and structure of new chiral squaric acid monoaminoalcohols and diaminoalcohols and their use as catalysts in asymmetric reduction of ketones and diketones
Zhou, Hai-Bing,Zhang, Ji,Lü, Shou-Mao,Xie, Ru-Gang,Zhou, Zhong-Yuan,Choi, Michael C.K,Chan, Albert S.C,Yang, Teng-Kuei
, p. 9325 - 9333 (2007/10/03)
Many chiral squaric acid aminoalcohols and C2-symmetric diaminoalcohols have been synthesized and their in situ formed chiral boron heterocycles have been used as catalysts for the enantioselective reduction of prochiral ketones and diketones by borane to give alcohols with up to 99% enantiomeric excess and 99% yield. The effects of solvent, catalyst-substrate ratio and temperature were also investigated.
