56318-83-3Relevant articles and documents
Enantioselective synthesis of 3-substituted dihydrobenzofurans through iridium-catalyzed intramolecular hydroarylation
Nishimura, Takahiro,Sakamoto, Kana
supporting information, p. 684 - 690 (2021/02/06)
Intramolecular hydroarylationviaC-H activation is one of the most powerful methods to synthesize carbo- and heterocyclic compounds, whereas we still have room for developing a highly enantioselective variant of the reaction. Here we describe Ir-catalyzed enantioselective intramolecular hydroarylation ofm-allyloxyphenyl ketones. The enantioselective cyclization was efficiently catalyzed by a cationic iridium complex coordinated with a conventional chiral bisphosphine ligand to give benzofurans in high yields with high enantioselectivity. A carbonyl group of ketones functioned as an effective directing group for the C-H activation. In terms of synthetic utility, we also achieved one-pot synthesis of chiral 3-substituted dihydrobenzofurans from readily available allylic carbonates andm-hydroxyacetophenonesviasequential Pd-catalyzed allylic substitution and Ir-catalyzed intramolecular hydroarylation.
Highly selective hydrosilylation of equilibrating allylic azides
Liu, Ruzhang,Liu, Yongmei,Wang, Juan,Wei, Zhen,Xue, Huaiguo
supporting information, p. 5038 - 5041 (2020/05/18)
The Pt-catalyzed hydrosilylation of equilibrating allylic azides is reported. The reaction provides only one out of four possible hydrosilylation products in good yields and with very high chemoselectivity (alk-1-enevs.alk-2-ene), regioselectivity (linearvs.branched), and excellent functional group tolerance.
Synthesis method of 3-azidopropylsilane
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Paragraph 0039; 0040, (2020/06/05)
The invention discloses a synthetic method of 3-azidopropylsilane, wherein the method comprises the steps: firstly, allyl azide is synthesized by allyl bromide, and because the allyl azide is easy togenerate [3,3] rearrangement reaction at room temperatur
In Situ Generated Gold Nanoparticles on Active Carbon as Reusable Highly Efficient Catalysts for a Csp3 ?Csp3 Stille Coupling
Holz, Julia,Pfeffer, Camilla,Zuo, Hualiang,Beierlein, Dennis,Richter, Gunther,Klemm, Elias,Peters, René
supporting information, p. 10330 - 10334 (2019/06/27)
Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional Csp2-Csp2 cross-coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form Csp3-Csp3 bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross-coupling reaction of an organic halide and an organometallic reagent.
BOTPPI, a new Wittig salt for the synthesis of 12-(S)-hydroxy- eicosatetraenoic acid [12-(S)-HETE]
Christiansen, Michael A.,Andrus, Merritt B.
supporting information; experimental part, p. 4805 - 4808 (2012/09/22)
An efficient route to (Z)-(8-benzyloxy-8-oxooct-3-en-1-yl) triphenylphosphonium iodide, or BOTPPI, is disclosed, complete with full experimental details, NMR spectra, and HRMS data. BOTPPI serves as a surrogate for (Z)-(8-methoxy-8-oxooct-3-en-1-yl)triphe
A catalytic asymmetric chlorocyclization of unsaturated amides
Jaganathan, Arvind,Garzan, Atefeh,Whitehead, Daniel C.,Staples, Richard J.,Borhan, Babak
supporting information; scheme or table, p. 2593 - 2596 (2011/05/02)
The asymmetric chlorocyclization of unsaturated amides catalyzed by (DHQD)2PHAL yields oxazoline and dihydrooxazine derivatives (see scheme). The reaction is operationally simple and employs 1-2 mol % of the commercially available (DHQD)2PHAL (hydroquinidine 1,4-phthalazinediyl diether) catalyst. Different substitution patterns of the olefin as well as aromatic and aliphatic olefin substituents are well tolerated. DCDPH=N,N-dichloro-5,5-diphenylhydantoin. Copyright
Factors influencing the autoxidation of fatty acids: Effect of olefin geometry of the nonconjugated diene
Tallman, Keri A.,Roschek Jr., Bill,Porter, Ned A.
, p. 9240 - 9247 (2007/10/03)
Autoxidations of cis,cis, cis,trans, and trans,trans nonconjugated octadecadienoates and pentadecadienes were carried out in the presence of α-tocopherol to investigate the effect of olefin geometry on this oxidation process and provide insight into the factors that influence the autoxidation of fatty acids. We have found that as the trans character of the diene increases, the amount of O2 trapping at the central (bis-allylic) position of the pentadienyl radical also increases. In addition, the rate constant for β-fragmentation (kβ ≈ 10 6 s-1) of the bis-allylic peroxyl radical decreased on going from the cis,cis to the trans,trans diene. We have also found that for the cis,trans nonconjugated dienes, there is a preference for trapping of the pentadienyl radical by O2 at the transoid end, generating the cis,trans conjugated hydroperoxide as the major product.
Large-scale preparation of (9Z,12E)-[1-13C]-octadeca-9,12-dienoic acid, (9Z,12Z,15E)-[1-13C]-octadeca-9,12,15-trienoic acid and their [1-13C] all-cis isomers
Loreau,Maret,Poullain,Chardigny,Sebedio,Beaufrere,Noel
, p. 65 - 78 (2007/10/03)
Several grams of labelled trans linoleic and linolenic acids with high chemical and isomeric purities (>97%) have been prepared for human metabolism studies. A total of 12.5 g of (9Z,12E)-[1-13C]-octadeca-9,12-dienoic acid and 6.3 g of (9Z,12Z,15E)-[1-13C]-octadeca-9,12,15-trienoic acid were obtained in, respectively, seven steps (7.8% overall yield) and 11 steps (7% overall yield) from 7-bromo-heptan-1-ol. The trans bromo precursors used for the labelling were synthesised by using copper-catalysed couplings. The trans fatty acids were then obtained via the nitrile derivatives. A total of 23.5 g of (9Z,12Z)-[1-13C]-octadeca-9,12-dienoic acid and 10.4 g of (9Z,12Z,15Z)-[1-13C]-octadeca-9,12,15-trienoic acid were prepared in five steps in, respectively, 32 and 18% overall yield. Large quantities of bromo and chloro precursors were synthesised from the commercially available acid according to Barton's procedure. In all cases, the main impurities (>0.5%) of each labelled fatty acid have been characterised. Copyright (C) 2000 Elsevier Science Ireland Ltd.
5-F2t-isoprostane, a human hormone?
Taber, Douglass F.,Kanai, Kazuo,Pina, Richard
, p. 7773 - 7777 (2007/10/03)
Syntheses of the four enantiomerically pure diastereomers of 5-F2t-isoprostane (5-8) are described. The key step is the lipase-catalyzed chemo-enzymatic resolution of the racemic diol 40 to give the mono-acetates 41 and 42. The enantiomerically
Bromide assisted addition of hydrogen bromide to alkynes and allenes
Weiss, Hilton M.,Touchette, Kim M.
, p. 1523 - 1528 (2007/10/03)
The addition of 0.1 M quaternary ammonium bromide to a solution of 20% trifluoroacetic acid in methylene chloride causes a large rate increase in the reaction of non-conjugated alkynes. The initial vinyl bromide product reacts further to provide a mixture of isomeric vinyl bromides and dibromides. At high salt concentrations however, the secondary reactions are prevented and only the initial vinyl bromide is found. In contrast to the corresponding addition to alkenes, the predominant mechanism is proposed to involve a one-step, concerted, nucleophilic attack by halide ion upon an acid-alkyne π-complex which produces the vinyl halide directly. A minor path involving syn addition is also seen. At all salt concentrations, allenes produce significant amounts of rearrangement products suggesting the significant involvement of a cationic mechanism.