58845-50-4Relevant academic research and scientific papers
Development and application of versatile bis-hydroxamic acids for catalytic asymmetric oxidation
Barlan, Allan U.,Zhang, Wei,Yamamoto, Hisashi
, p. 6075 - 6087 (2007)
In this article, we describe the development and preliminary results of our new designed C2-symmetric bis-hydroxamic acid (BHA) ligands and the application of the new ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols as well as homoallylic alcohols. From this success we demonstrate the versatile nature of BHA in the molybdenum catalyzed asymmetric oxidation of unfunctionalized olefins and sulfides.
Metathesis at an Implausible Site: A Formal Total Synthesis of Rhizoxin D
Karier, Pol,Ungeheuer, Felix,Ahlers, Andreas,Anderl, Felix,Wille, Christian,Fürstner, Alois
supporting information, p. 248 - 253 (2018/12/13)
The new approach to the anticancer agent rhizoxin D described herein does not cohere with the conventional logic of metathesis, according to which macrocycles are best closed at a disubstituted olefinic site; rather, the trisubstituted C11?C12 alkene flanked by an allylic -OH group served as the pivot point for synthesis. This motif was attained in good yield and excellent selectivity by a sequence of alkyne metathesis, trans-hydrostannation and cross coupling. Because the exact same substructure is prominently featured in numerous other natural products, the underpinning strategy, though unusual, might bear more general relevance.
Multigram synthesis of 1-O-acetyl-3-O-(4-methoxybenzyl)-4-N-(9-fluorenylmethoxycarbonyl)-4-N-methyl-l-pyrrolosamine
Burk, Matthew,Wilson, Nolan,Herzon, Seth B.
supporting information, p. 3231 - 3234 (2015/02/19)
The synthesis of 1-O-acetyl-3-O-(4-methoxybenzyl)-4-N-(9-fluorenylmethoxycarbonyl)-4-N-methyl-l-pyrrolosamine (7), which constitutes a protected form of the N,N-dimethyl-l-pyrrolosamine residues found within the antiproliferative bacterial metabolites (-)
Sensing remote chirality: Stereochemical determination of β-, γ-, and δ-chiral carboxylic acids
Tanasova, Marina,Anyika, Mercy,Borhan, Babak
supporting information, p. 4274 - 4278 (2015/04/14)
Determining the absolute stereochemisty of small molecules bearing remote nonfunctionalizable stereocenters is a challenging task. Presented is a solution in which appropriately substituted bis(porphyrin) tweezers are used. Complexation of a suitably derivatized β-, γ-, or δ-chiral carboxylic acid to the tweezer induces a predictable helicity of the bis(porphyrin), which is detected as a bisignate Cotton Effect (ECCD). The sign of the ECCD curve is correlated with the absolute stereochemistry of the substrate based on the derived working mnemonics in a predictable manner.
Total syntheses of rubiginone A2, C2, and fujianmycin A
Vanga, Devendar G.,Kaliappan, Krishna P.
, p. 12716 - 12722 (2014/04/03)
The total syntheses of rubiginone A2, C2 and fujianmycin A are described. The synthesis involves Diels-Alder/aromatization and photo chemical reactions as key steps to construct the tetracyclic frame of benz[a]anthraquinone skeleton.
Exploration of chiral induction on epoxides in lipase-catalyzed epoxidation of alkenes using (2R,3S,4R,5S)-(-)-2,3:4,6-di-O-isopropylidiene-2-keto-l-gulonic acid monohydrate
Sarma, Kuladip,Goswami, Amrit,Goswami, Bhabesh C.
experimental part, p. 1295 - 1300 (2009/10/17)
Epoxidation of alkenes by peracid, generated in situ from (2R,3S,4R,5S)-(-)-2,3:4,6-di-O-isopropylidiene-2-keto-l-gulonic acid monohydrate [(-)-DIKGA] and hydrogen peroxide by lipase catalysis induces chirality on the product epoxides with moderate to good enantioselectivity (35-71%). Alkoxy/aralkyloxy styrenes however did not undergo any epoxidation. (R)-(+)-4-Hydroxy styrene-7,8-oxide was formed and isolated with moderate enantiomeric excess (57%) but was found to have poor stability.
Enantioselective epoxidation of allylic alcohols by a chiral complex of vanadium: An effective controller system and a rational mechanistic model
Zhang, Wei,Basak, Arindrajit,Kosugi, Yuji,Hoshino, Yujiro,Yamamoto, Hisashi
, p. 4389 - 4391 (2007/10/03)
(Chemical Equation Presented) Bishydroxamic acid derivatives are used as ligands for a vanadium catalyst in the preparation of epoxy alcohols (see scheme). The methodology uses aqueous tert-butyl hydroperoxide (TBHP) as an achiral oxidant, low catalyst loading, low reaction temperatures (0°C to room temperature), and simple workup procedures. The reaction is applied to the kinetic resolution of a secondary allylic alcohol and the preparation of small epoxy alcohols. R1, R2, R3: alkyl, aryl, H.
Stereochemical analysis of isopentenyl diphosphate isomerase type II from Staphylococcus aureus using chemically synthesized (S)- and (R)-[2- 2H]Isopentenyl diphosphates
Kao, Chai-Lin,Kittleman, William,Zhang, Hua,Seto, Haruo,Liu, Hung-Wen
, p. 5677 - 5680 (2007/10/03)
(Chemical Equation Presented) To study the catalysis of isopentenyl diphosphate (IPP) isomerase type II from Staphylococcus aureus, which is a flavoprotein catalyzing the interconversion of IPP and dimethylallyl diphosphate, we have chemically synthesized (S)- and (R)-[2-2H]IPP and carried out stereochemical analysis of the reaction. Our results show that the C-2 deprotonation of IPP by this enzyme is pro-R stereospecific, suggesting a similar stereochemical course as the type I enzyme.
Liquid-Phase Synthesis of Chiral Tartrate Ligand Library for Enantioselective Sharpless Epoxidation of Allylic Alcohols
Guo, Hong-Chao,Shi, Xue-Yan,Wang, Xian,Liu, Shang-Zhong,Wang, Min
, p. 2042 - 2047 (2007/10/03)
This paper reports a successful development of a group of efficient soluble polymer-supported chiral tartrate ligands by liquid-phase synthesis for Sharpless epoxidation of a variety of allylic alcohols through ligand diversity. The influence of substituent in chiral tartrate ligands on the enantioselectivities of the reaction was disclosed. Moderate chemical yields and good enantiomeric excesses were obtained by using soluble polymer-supported tartrate ester in the epoxidation of allylic alcohols with Ti(O-i-Pr) 4/tert-butyl hydroperoxide.
Base-Induced Heterochiral Dimerization of an Oxiranyl Carbaldimine: Stereoselective Synthesis of a Highly Functionalized Aziridine
Alickmann, Dirk,Froehlich, Roland,Wuerthwein, Ernst-Ulrich
, p. 1527 - 1530 (2007/10/03)
matrix presented Treatment of the oxiranyl carbaldimine with base (LDA or LDA/KOtBu) leads in an one-step procedure to the polyfunctionalized aziridine. This highly diastereoselective reaction is explained by a new type of an Aza-Darzens reaction, in which one enantiomer of the starting material is deprotonated to form an oxiranyl anion, which attacks the imine carbon atom of the other enantiomer (mutual kinetic resolution by double diastereofacial selection).
