Enantioselective reduction and deracemisation using the non-conventional yeast Pichia glucozyma in water/organic solvent biphasic systems: preparation of (S)-1,2-diaryl-2-hydroxyethanones (benzoins)
作者:Maria Caterina Fragnelli、Pilar Hoyos、Diego Romano、Raffaela Gandolfi、Andrés R. Alcántara、Francesco Molinari
DOI:10.1016/j.tet.2011.11.014
日期:2012.1
applied in the synthesis of enantiomerically pure (S)-benzoin through two different methodologies catalysed by whole cells from the non-conventional yeast Pichia glucozyma: the stereoselective monoreduction of benzil and the deracemisation of benzoin. The presence of the organic solvent influences the redox systems implied in the reactions, avoiding the formation of the corresponding diols, increasing
Dynamic Kinetic Resolution of Benzoins by Lipase−Metal Combo Catalysis
作者:Pilar Hoyos、María Fernández、José Vicente Sinisterra、Andrés R. Alcántara
DOI:10.1021/jo061060b
日期:2006.9.1
The synthesis of some noncommercial racemic 1,2-diaryl-2-hydroxyethanones (benzoins) is described, optimizing the previously reported methodologies. In a further step, the kinetic resolution of these substrates is reported, obtaining conversions of around 50% and eep higher than 99% in very short reaction times. As enzymatic catalyst, after screening of several enzymes, the lipase TL (from Pseudomonas
GO for it! An enantiopure galactoseoxidase (GO) enzyme model has been synthesized from readily available (R)‐binam and Cu(OTf)2 (see scheme; TEMPO=2,2,6,6‐tetramethyl‐piperidin‐1‐oxyl), and has been effectively used as an efficient chiral catalyst for the oxidative kinetic resolution of secondary alcohols. This is the first chiral copper‐catalyzed oxidative kinetic resolution of racemic benzoins and
大胆试试吧!对映纯半乳糖氧化酶(GO)酶模型已从现成的(R)-比纳姆和Cu(OTf)2(参见方案; TEMPO = 2,2,6,6-四甲基-哌啶-1-氧)合成,并且已有效地用作仲醇的氧化动力学拆分的有效手性催化剂。这是外消旋安息香的第一个手性铜催化的氧化动力学拆分,也是合成高度重要的对映体富集的安息香的最简单方法。
Chiral Cobalt-Catalyzed Enantiomer-Differentiating Oxidation of Racemic Benzoins by Using Molecular Oxygen as Stoichiometric Oxidant
An efficient enantioselective oxidative reaction catalyzed by a chiral cobalt complex has been developed by using molecularoxygen as the stoichiometric oxidant (see scheme). The very mild reaction conditions of the catalytic system provide access to a wide range of benzoins (α‐hydroxyketones) in high yield and excellent enantioselectivity (s (kf/ks) up to 47). This method is very versatile because
通过使用分子氧作为化学计量的氧化剂,已经开发了一种有效的由手性钴配合物催化的对映选择性氧化反应(参见方案)。催化系统的反应条件非常温和,可以高产率获得各种安息香(α-羟基酮),并具有出色的对映选择性(s(k f / k s)至47)。该方法用途广泛,因为氧化过程的唯一副产品是水,这使我们的系统更加环保,绿色。
Heat-sensitive adhesive agent and heat-sensitive adhesive sheet
申请人:Ricoh Company, Ltd.
公开号:EP1897925A1
公开(公告)日:2008-03-12
Provided is a heat-sensitive adhesive agent that mainly comprises a thermoplastic resin and a heat-meltable substance capable of melting upon heating, and further comprises swellable mica.