16354-93-1Relevant articles and documents
An ingenious method for the determination of the relative and absolute configurations of compounds containing aryl-glycerol fragments by1H NMR spectroscopy
Zhang, Xu,Lu, Kai-Zhou,Yan, Hai-Wei,Feng, Zi-Ming,Yang, Ya-Nan,Jiang, Jian-Shuang,Zhang, Pei-Cheng
, p. 8107 - 8116 (2021/03/03)
A concise method was established to determine the relative and absolute configurations of aryl-glycerols that depend on the chemical shift differences (Δδ) of the diastereotopic methylene protons (H-3) by1H NMR spectroscopy. When using DMSO-d6as the preferred solvent, thethreoconfiguration corresponded to a larger ΔδH3a-H3bvalue (>0.15 ppm), whereas theerythroconfiguration (a smaller value. Furthermore, the absolute configurations were determined with the aid of a simple acylation reaction through camphanoyl chloride. In thethreoenantiomers, the Δδvalue of the 1R,2Rconfiguration was 0.20 ppm. In theerythroenantiomers, the Δδvalue of 1R,2Swas >0.09 ppm, and that of 1S,2Rwas 3. In addition, this method was also verified by a quantum1H NMR calculation.
Molybdenum-Catalyzed Hydroxyl-Directed Anti-Dihydroxylation of Allylic and Homoallylic Alcohols
Fan, Pei,Su, Shixia,Wang, Chuan
, p. 6820 - 6826 (2018/06/22)
A catalytic hydroxyl-directed anti-dihydroxylation of allylic and homoallylic alcohols has been developed. This operationally simple method was successfully applied to the direct anti-monodihydroxylation of allylic alcohols containing at least one distal olefinic unit. Under the catalysis of commercially available MoO2(acac)2, an array of hydroxylated dienes were successfully converted into various 1,2,3-triols using hydrogen peroxide as an environmentally benign oxidant under aerobic conditions, notably, in complete regioselectivities and in the most cases in diastereospecific pathway.
Scalable, stereoselective syntheses of α,β-difluoro-γ-amino acids
Patel, Alpesh Ramanlal,Hu, Xiang-Guo,Lawer, Aggie,Ahmed, Md. Iqbal,Au, Catherine,Jwad, Rasha,Trinh, Johny,Gonzalez, Christina,Hannah, Elizabeth,Bhadbhade, Mohan M.,Hunter, Luke
, p. 3305 - 3317 (2016/05/19)
Backbone-fluorinated gamma-amino acids are novel shape-controlled building blocks that have potential utility in a variety of biological contexts. However, their synthesis poses challenges in terms of chemo-, regio- and stereoselectivity, and this has proven to be the major bottleneck in the ongoing development of their various biological applications. To address this problem, several new synthetic strategies were investigated in this work. This has led to the identification of new methods that are superior in terms of yield and stereocontrol.
Expedient synthesis of C-aryl carbohydrates by consecutive biocatalytic benzoin and aldol reactions
Hern??ndez, Karel,Parella, Teodor,Joglar, Jesffls,Bujons, Jordi,Pohl, Martina,Clap??s, Pere
, p. 3335 - 3346 (2015/03/05)
The introduction of aromatic residues connected by a C-C bond into the non-reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C-aril-sLex). In this work, an expedient asymmetric de novo synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the a-hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary d-fructose-6-phosphate aldolase and l-rhamnulose-1-phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphatedependent aldolases require. In this way, 6-C-aryl-l -sorbose, 6-C-aryl-l-fructose, 6-C-aryl- l-tagatose, and 5-C-aryl-l-xylose derivatives are prepared by using this methodology.
Conversion of oxiranes and CO2 to organic cyclic carbonates using a recyclable, bifunctional polystyrene-supported organocatalyst
Whiteoak, Christopher J.,Henseler, Andrea H.,Ayats, Carles,Kleij, Arjan W.,Pericas, Miquel A.
, p. 1552 - 1559 (2014/03/21)
The development of a heterogeneous one-component bifunctional catalyst system able to catalyse the conversion of carbon dioxide and oxiranes to organic cyclic carbonates at low temperature (45 °C) is reported. The bifunctional system can be easily recycled and reactivated when required. When compared with other heterogeneous organocatalysts for the same transformation, the reported catalyst is active at much milder temperatures, thus emphasising the optimal sustainability profile of the new catalyst system.
The 1H NMR method for the determination of the absolute configuration of 1,2,3-prim,sec,sec-triols
Lallana, Enrique,Freire, Felix,Seco, Jose Manuel,Quinoa, Emilio,Riguera, Ricardo
, p. 4449 - 4452 (2007/10/03)
The absolute configuration of 1,2,3-prim,sec,sec-triols can be assigned by comparison of the 1H NMR spectra of the tris-(R)- and the tris-(S)-MPA ester derivatives. An experimental demonstration of this correlation with 24 triols of known absolute configuration and a protocol using two parameters-ΔδRS(H3) and the difference between ΔδRS(H2) and ΔδRS(H3) = |Δ(ΔδRS)|-for its application to the determination of the absolute configuration of other triols are presented.
Study of the regio- and enantioselectivity of the reactions of osmium tetroxide with allylic alcohols and allylic sulfonamides
Xu, Daqiang,Park, Christine Y.,Barry Sharpless
, p. 2495 - 2498 (2007/10/02)
The regioselectivities of the osmylation of geraniol, its derivatives and geranyl sulfonamides suggest the presence of a moderate attractive interaction between OsO4 and the allylic groups bearing acidic protons. This allylic directing effect may be due to the development of a hydrogen bonding interaction between OsO4 and the substrate during the osmylation process. The potential for a hydrogen bond can also have a substantial effect on the enantioselectivities of the osmium tetroxide catalyzed asymmetric dihydroxylation of allylic alcohols.
Synthesis of O-Protected (R)-2-Hydroxy Aldehyde and Their Hydrocyanation
Effenberger, Franz,Hopf, Martin,Ziegler, Thomas,Hudelmayer, Jochen
, p. 1651 - 1659 (2007/10/02)
The synthesis of O-silyl- and O-benzyl-protected (R)-2-hydroxy aldehydes (R)-6 from (R)-2-hydroxy carboxylic acids (R)-1 is described.While attempts for their diastereoselective hydrocyanation with hydrocyanic acid and (R)-oxynitrilase as catalyst have not been successful, the cyano silylation with trimethylsilyl cyanide occurred diastereoselectively with a ratio of 81:19 preferring the threo form without racemization at C-2 of the 2-hydroxy aldehyde. Key Words : (R)-2-Hydroxy aldehydes, O-protected / Hydrocyanation
CYCLOFUNCTIONALISATION OF EPOXYALCOHOL DERIVATIVES. 2. STEREO- AND REGIOSPECIFIC CONVERSION TO 1,3-DIOXOLANES
McCombie, Stuart W.,Metz, William A.
, p. 383 - 386 (2007/10/02)
2,3-Epoxyalcohols react with paraformaldehyde and either cesium carbonate or potassium carbonate/phase-transfer catalyst in polar, aprotic solvents to give excellent yields of 4-(1-hydroxyalkyl)-1,3-dioxolanes, with inversion at C-2.
HIGHLY STEREOSELECTIVE SYNTHESIS OF OPTICALLY ACTIVE MASKED SYN-α,β-DIHYDROXY ALDEHYDES.
Annunziata, Rita,Cinquini, Mauro,Cozzi, Franco,Raimondi, Laura,Stefanelli, Stefania
, p. 3139 - 3142 (2007/10/02)
Dihydroquinidine acetate promoted osmylation of acetals of E-α,β-unsaturated aldehydes occurs with up to 40:1 stereoselection to afford the corresponding protected syn-α,β-dihydroxy aldehydes.
