22520-39-4Relevant articles and documents
Origin of α-Hydroxy Ketones in the Osmium Tetroxide-Catalyzed Asymmetric Dihydroxylation of Alkenes
Lohray, Braj B.,Bhushan, Vidya,Kumar, R. Krishna
, p. 1375 - 1380 (1994)
The origin and the mechanism of formation of α-hydroxy ketones in the osmium tetroxide-catalyzed asymmetric cis-dihydroxylation (ADH) of alkenes in the presence of tert-butyl hydroperoxide is described.The formation of α-hydroxy ketones has been established to proceed through either the hydration of monooxobisglycolate ester 2 followed by oxidation with tert-butyl hydroperoxide (TBHP) or by acid-catalyzed addition of TBHP on the intermediate bisglycolate ester 2.On the basis of the mechanistic insight, it has been possible to shut down the formation of α-hydroxy ketones and other side products in the ADH reaction, even when TBHP is used as an oxygen source.It is possible to prepare α-hydroxy ketones in good yields but the optical purity of ketols has been found to be very low, which not only shed significant light on the mechanism of their formation, but also delineated the improbability of syntesizing them in optically active forms by ADH reaction of alkenes.
Structural Study of Bromide-Bridged Pd Chain Complex with Weak CH···O Hydrogen Bonds
Rasel Mian, Mohammad,Iguchi, Hiroaki,Miyata, Momoka,Takaishi, Shinya,Yamakawa, Hiromichi,Terashige, Tsubasa,Miyamoto, Tatsuya,Okamoto, Hiroshi,Yamashita, Masahiro
, p. 646 - 651 (2018/08/06)
A novel Br-bridged Pd chain complex, [Pd(hxn)2Br](TsO)2 (2) (TsO– = p-toluenesulfonate), was synthesized from a new in-plane ligand (3S,4S)-3,4-diaminohexane (hxn). 2 forms PdII/PdIV mixed-valence state, as confirmed by single-crystal X-ray structure analysis and polarized Raman spectra. The hxn ligand provides the additional hydrogen bonds (CH···O) between the methyl group of the ligands and the O atoms of TsO– anions, which are weaker than those observed in the chain complex with hydroxy group, [Pd(dabdOH)2Br]Br2 (1).
Assessing the stereoselectivity of: Serratia marcescens CECT 977 2,3-butanediol dehydrogenase
Médici, Rosario,Stammes, Hanna,Kwakernaak, Stender,Otten, Linda G.,Hanefeld, Ulf
, p. 1831 - 1837 (2017/07/15)
α-Hydroxy ketones and vicinal diols constitute well-known building blocks in organic synthesis. Here we describe one enzyme that enables the enantioselective synthesis of both building blocks starting from diketones. The enzyme 2,3-butanediol dehydrogenase (BudC) from S. marcescens CECT 977 belongs to the NADH-dependent metal-independent short-chain dehydrogenases/reductases family (SDR) and catalyses the selective asymmetric reductions of prochiral α-diketones to the corresponding α-hydroxy ketones and diols. BudC is highly active towards structurally diverse diketones in combination with nicotinamide cofactor regeneration systems. Aliphatic diketones, cyclic diketones and alkyl phenyl diketones are well accepted, whereas their derivatives possessing two bulky groups are not converted. In the reverse reaction vicinal diols are preferred over other substrates with hydroxy/keto groups in non-vicinal positions.
Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l-1,2-Diols with Chiral Nucleophilic Catalysts
Fujii, Kazuki,Mitsudo, Koichi,Mandai, Hiroki,Suga, Seiji
supporting information, p. 2778 - 2788 (2017/08/23)
An extremely efficient acylative kinetic resolution of d,l-1,2-diols in the presence of only 0.5 mol% of binaphthyl-based chiral N,N-4-dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert-alcohol unit(s) of the catalyst and the 1,2-diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2-diols with high selectivity factors. The kinetic resolution of d,l-hydrobenzoin and trans-1,2-cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 °C); (iii) high substrate concentration (1.0 M); and (iv) short reaction time (30 min). (Figure presented.).
Amine Catalysis for the Organocatalytic Diboration of Challenging Alkenes
Farre, Albert,Soares, Kaline,Briggs, Rachel A.,Balanta, Angelica,Benoit, David M.,Bonet, Amadeu
supporting information, p. 17552 - 17556 (2016/11/28)
The generation of in situ sp2–sp3diboron adducts has revolutionised the synthesis of organoboranes. Organocatalytic diboration reactions have represented a milestone in terms of unpredictable reactivity of these adducts. However, current methodologies have limitations in terms of substrate scope, selectivity and functional group tolerance. Here a new methodology based on the use of simple amines as catalyst is reported. This methodology provides a completely selective transformation overcoming current substrate scope and functional/protecting group limitations. Mechanistic studies have been included in this report.
Selective transition-metal-free vicinal cis-dihydroxylation of saturated hydrocarbons
Bering, Luis,Antonchick, Andrey P.
, p. 452 - 457 (2016/12/30)
A transition-metal-free cis-dihydroxylation of saturated hydrocarbons under ambient reaction conditions has been developed. The described approach allows a direct and selective synthesis of vicinal diols. The new reaction thereby proceeds via radical iodination and a sequence of oxidation steps. A broad scope of one-pot dual C(sp3)-H bond functionalization for the selective synthesis of vicinal syn-diols was demonstrated.
Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
, p. 1972 - 1978 (2015/02/19)
We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
Biocatalytic production of alpha-hydroxy ketones and vicinal diols by yeast and human aldo-keto reductases
Calam, Eduard,Porté, Sergio,Fernández, M. Rosario,Farrés, Jaume,Parés, Xavier,Biosca, Josep A.
, p. 195 - 203 (2013/05/08)
The α-hydroxy ketones are used as building blocks for compounds of pharmaceutical interest (such as antidepressants, HIV-protease inhibitors and antitumorals). They can be obtained by the action of enzymes or whole cells on selected substrates, such as diketones. We have studied the enantiospecificities of several fungal (AKR3C1, AKR5F and AKR5G) and human (AKR1B1 and AKR1B10) aldo-keto reductases in the production of α-hydroxy ketones and diols from vicinal diketones. The reactions have been carried out with pure enzymes and with an NADPH-regenerating system consisting of glucose-6-phosphate and glucose-6-phosphate dehydrogenase. To ascertain the regio and stereoselectivity of the reduction reactions catalyzed by the AKRs, we have separated and characterized the reaction products by means of a gas chromatograph equipped with a chiral column and coupled to a mass spectrometer as a detector. According to the regioselectivity and stereoselectivity, the AKRs studied can be divided in two groups: one of them showed preference for the reduction of the proximal keto group, resulting in the S-enantiomer of the corresponding α-hydroxy ketones. The other group favored the reduction of the distal keto group and yielded the corresponding R-enantiomer. Three of the AKRs used (AKR1B1, AKR1B10 and AKR3C1) could produce 2,3-butanediol from acetoin. We have explored the structure/function relationships in the reactivity between several yeast and human AKRs and various diketones and acetoin. In addition, we have demonstrated the utility of these AKRs in the synthesis of selected α-hydroxy ketones and diols.
Enantiomerically enriched trans-diols from alkenes in one pot: A multicatalyst approach
Hrdina, Radim,Mueller, Christian E.,Wende, Raffael C.,Wanka, Lukas,Schreiner, Peter R.
supporting information; experimental part, p. 2498 - 2500 (2012/04/10)
Multicatalysts consisting of non-natural oligopeptides with distinctly different catalytic moieties create molecular complexity in a multistep one-pot sequence starting from simple alkenes yielding highly enantiomerically enriched trans-diols. The Royal Society of Chemistry 2012.
Pt-based chiral organotin modified heterogeneous catalysts for the enantioselective hydrogenation of 3,4-hexanedione
Vetere, Virginia,Faraoni, María B.,Podestá, Julio C.,Casella, Mónica L.
, p. 209 - 214 (2013/02/23)
In this paper we have studied the liquid-phase enantioselective hydrogenation of 3,4-hexanedione using Pt-based catalysts, modified with chiral organotin compounds derived from the (-)-menthyl group: (-)-Pt-MenSnBu 3 and (-)-Men3Sn-Sn-(-)-Men3. The organotin chiral modifiers were carefully synthesized and characterized in order to obtain optically pure compounds. The catalysts were prepared through a controlled surface reaction between the supported transition metal and the organometallic compound, using techniques derived from Surface Organometallic Chemistry on Metals (SOMC/M). The organobimetallic catalytic systems were found to be active and enantioselective in the hydrogenation of 3,4-hexanedione, yielding an enantiomeric excess of 25-27% for 4-hydroxy-3-hexanone.
