7766-51-0Relevant articles and documents
The electrophilic cleavage of cyclopropylcarbinylstannanes. Confirmation of Traylor's prediction
Lucke,Young
, p. 807 - 810 (1991)
The reaction of cyclopropylcarbinyltrialkylstannanes (CPCSnR3) 1a (R = Me) and 1b (R = Bu) with sulfur dioxide in chloroform or methanol yields the homoallylic tin sulphinates 2a and 2b respectively. The reaction of 1a with iodine in chloroform yields predominantly 4-iodo-1-butene (3) and trimethyltin iodide while in methanol the corresponding reaction yields CPCSnMe2I (4) and methyl iodide.
Synthesis of Low-Viscosity Ionic Liquids for Application in Dye-Sensitized Solar Cells
Fang, Yanyan,Ma, Pin,Cheng, Hongbo,Tan, Guoyu,Wu, Jiaxin,Zheng, Jiaxin,Zhou, Xiaowen,Fang, Shibi,Dai, Yuhua,Lin, Yuan
, p. 4201 - 4206 (2019)
Two types of ionic liquids (ILs), 1-(3-hexenyl)-3-methyl imidazolium iodide and 1-(3-butenyl)-3-methyl imidazolium iodide, are synthesized by introducing an unsaturated bond into the side alkyl chain of the imidazolium cation. These new ionic liquids exhibit high thermal stability and low viscosity (104 cP and 80 cP, respectively). The molecular dynamics simulation shows that the double bond introduced in the alkane chain greatly changes the molecular system space arrangement and diminishes the packing efficiency, leading to low viscosity. The low viscosity of the synthesized ionic liquids would enhance the diffusion of redox couples. This enhancement is detected by fabricating dye-sensitized solar cells (DSSCs) with electrolytes containing the two ILs and I2. The highest efficiency of DSSCs is 6.85 % for 1-(3-hexenyl)-3-methyl imidazolium iodide and 5.93 % for 1-(3-butenyl)-3-methyl imidazolium iodide electrolyte, which is much higher than that of 5.17 % with the counterpart 1-hexyl-3-methyl imidazolium iodide electrolyte.
Cobalt-Catalyzed Regioselective Olefin Isomerization under Kinetic Control
Liu, Xufang,Zhang, Wei,Wang, Yujie,Zhang, Ze-Xin,Jiao, Lei,Liu, Qiang
supporting information, p. 6873 - 6882 (2018/05/30)
Olefin isomerization is a significant transformation in organic synthesis, which provides a convenient synthetic route for internal olefins and remote functionalization processes. The selectivity of an olefin isomerization process is often thermodynamically controlled. Thus, to achieve selectivity under kinetic control is very challenging. Herein, we report a novel cobalt-catalyzed regioselective olefin isomerization reaction. By taking the advantage of fine-tunable NNP-pincer ligand structures, this catalytic system features high kinetic control of regioselectivity. This mild catalytic system enables the isomerization of 1,1-disubstituted olefins bearing a wide range of functional groups in excellent yields and regioselectivity. The synthetic utility of this transformation was highlighted by the highly selective preparation of a key intermediate for the total synthesis of minfiensine. Moreover, a new strategy was developed to realize the selective monoisomerization of 1-alkenes to 2-alkenes dictated by installing substituents on the γ-position of the double bonds. Mechanistic studies supported that the in situ generated Co-H species underwent migratory insertion of double bond/β-H elimination sequence to afford the isomerization product. The less hindered olefin products were always preferred in this cobalt-catalyzed olefin isomerization due to an effective ligand control of the regioselectivity for the β-H elimination step.
Direct Generation of Triketide Stereopolyads via Merged Redox-Construction Events: Total Synthesis of (+)-Zincophorin Methyl Ester
Kasun, Zachary A.,Gao, Xin,Lipinski, Radoslaw M.,Krische, Michael J.
supporting information, p. 8900 - 8903 (2015/08/03)
(+)-Zincophorin methyl ester is prepared in 13 steps (longest linear sequence). A bidirectional redox-triggered double anti-crotylation of 2-methyl-1,3-propane diol directly assembles the triketide stereopolyad spanning C4-C12, significantly enhancing step economy and enabling construction of (+)-zincophorin methyl ester in nearly half the steps previously required.
Synthetic studies toward the brasilinolides: Controlled assembly of a protected C1-C38 polyol based on fragment union by complex aldol reactions
Paterson, Ian,Housden, Michael P.,Cordier, Christopher J.,Burton, Paul M.,Mühlthau, Friedrich A.,Loiseleur, Olivier
supporting information, p. 5716 - 5733 (2015/05/27)
The brasilinolides are an architecturally complex family of 32-membered macrolides, characterised by potent immunosuppressant and antifungal properties, which represent challenging synthetic targets. By adopting a highly convergent strategy, a range of asymmetric aldol/reduction sequences and catalytic protocols were employed to assemble a series of increasingly elaborate fragments. The controlled preparation of suitable C1-C19 and C20-C38 acyclic fragments 5 and 6, containing seven and 12 stereocentres respectively, was first achieved. An adventurous C19-C20 fragment union was then explored to construct the entire carbon chain of the brasilinolides. This pivotal coupling step could be performed in a complex boron-mediated aldol reaction to install the required C19 hydroxyl stereocentre when alternative Mukaiyama-type aldol protocols proved unrewarding. A protected C1-C38 polyol 93 was subsequently prepared, setting the stage for future late-stage diversification toward the various brasilinolide congeners. Throughout this work, asymmetric boron-mediated aldol reactions of chiral ketones with aldehydes proved effective both for controlled fragment assembly and coupling with predictable stereoinduction from the enolate component.
Enantiospecific intramolecular heck reactions of secondary benzylic ethers
Harris, Michael R.,Konev, Mikhail O.,Jarvo, Elizabeth R.
supporting information, p. 7825 - 7828 (2014/06/23)
Enantioenriched methylenecyclopentanes are synthesized by stereospecific, nickel-catalyzed Heck cyclizations of secondary benzylic ethers. The reaction proceeds in high yield and enantiospecificity for benzylic ethers of both π-extended and simple arenes. Ethers with pendant 1,2-disubstituted olefins form trisubstituted olefins with control of both absolute configuration and alkene geometry. Diastereoselective synthesis of a polycyclic furan is demonstrated.
Chemoenzymatic asymmetric total synthesis of nonanolide (Z)-cytospolides D, E and their stereoisomers
Rej, Rohan Kalyan,Nanda, Samik
, p. 860 - 871 (2014/03/21)
Chemoenzymatic asymmetric total synthesis of the (Z)-isomer of the naturally occurring decanolide cytospolides D, E and six stereoisomers is reported. The main highlight of the synthetic venture involves ring-closing metathesis (RCM) reaction of a suitably functionalized ester compound, which was assembled by the Yamaguchi coupling of the required acid and alcohol fragments. The alcohol fragment was ac- cessed by two alternative chemoenzymatic processes, one being hydroxynitrile lyase mediated hydrocyanation, whereas lipase-catalyzed transesterification was the key sep in the second route. The acid fragment was constructed by an enantioselective enzymatic desymmetrization (EED) of prochiral 2-methyl-1,3-propanediol and Corey-Bakshi-Shibata (CBS) mediated stereoselective carbonyl reduction.
Chemoenzymatic Asymmetric Total Synthesis of Nonanolide (Z)-Cytospolides D, e and Their Stereoisomers
Rej, Rohan Kalyan,Nanda, Samik
, p. 860 - 871 (2015/10/05)
Chemoenzymatic asymmetric total synthesis of the (Z)-isomer of the naturally occurring decanolide cytospolides D, E and six stereoisomers is reported. The main highlight of the synthetic venture involves ring-closing metathesis (RCM) reaction of a suitably functionalized ester compound, which was assembled by the Yamaguchi coupling of the required acid and alcohol fragments. The alcohol fragment was accessed by two alternative chemoenzymatic processes, one being hydroxynitrile lyase mediated hydrocyanation, whereas lipase-catalyzed transesterification was the key sep in the second route. The acid fragment was constructed by an enantioselective enzymatic desymmetrization (EED) of prochiral 2-methyl-1,3-propanediol and Corey-Bakshi-Shibata (CBS) mediated stereoselective carbonyl reduction.
Skeletal and stereochemical diversification of tricyclic frameworks inspired by Ca2+-ATPaSe inhibitors, artemisinin and transtaganolide D
Oguri, Hiroki,Yamagishi, Yutaka,Hiruma, Takahisa,Oikawa, Hideaki
supporting information; experimental part, p. 601 - 604 (2009/09/25)
(Chemical Equation Presented) Inspired by the common skeletal motifs of Ca2+-ATPases inhibitors involving artemisinin and transtaganolide D, small molecule collections with the three-dimensional structural diversity of tricyclic systems were designed and expeditiously synthesized (4-5 steps). A synthetic strategy featuring stereochemical diversification of ring-junctions and control of cyclizatlon modes was devised to access varied molecular architectures in a systematic fashion.
Synthetic studies toward jatrophane diterpenes from Euphorbia characias. enantioselective synthesis of (-)-15-O-Acetyl-3-O-propionyl-17-norcharaciol
Helmboldt, Hannes,Hiersemann, Martin
scheme or table, p. 1698 - 1708 (2009/10/02)
The enantioselective synthesis of (+)-17-norcharaciol is described. An uncatalyzed intramolecular carbonyl-ene reaction and a ring-closing metathesis were used as key C/C-connecting transformations to assemble the trans-bicyclo[10.3.0]pentadecane norditerpenoid core. We also report the evolution of our synthetic strategy toward the fully substituted characiol skeleton and the experiences from this venture.
