18654-73-4Relevant academic research and scientific papers
Selecting double bond positions with a single cation-responsive iridium olefin isomerization catalyst
Camp, Andrew M.,Kita, Matthew R.,Blackburn, P. Thomas,Dodge, Henry M.,Chen, Chun-Hsing,Miller, Alexander J.M.
supporting information, p. 2792 - 2800 (2021/03/01)
The catalytic transposition of double bonds holds promise as an ideal route to alkenes of value as fragrances, commodity chemicals, and pharmaceuticals; yet, selective access to specific isomers is a challenge, normally requiring independent development of different catalysts for different products. In this work, a single cation-responsive iridium catalyst selectively produces either of two different internal alkene isomers. In the absence of salts, a single positional isomerization of 1-butene derivatives furnishes 2-alkenes with exceptional regioselectivity and stereoselectivity. The same catalyst, in the presence of Na+, mediates two positional isomerizations to produce 3-alkenes. The synthesis of new iridium pincer-crown ether catalysts based on an aza-18-crown-6 ether proved instrumental in achieving cation-controlled selectivity. Experimental and computational studies guided the development of a mechanistic model that explains the observed selectivity for various functionalized 1-butenes, providing insight into strategies for catalyst development based on noncovalent modifications.
Method for synthesizing 1, 2-disubstituted olefin through reaction of terminal group olefin and sulfoxide
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Paragraph 0053-0054; 0057-0062; 0083, (2021/02/10)
The invention discloses a method for synthesizing 1, 2-disubstituted olefin by reaction of terminal olefin and sulfoxide. According to the method, terminal olefin with sulfoxide make reaction in one pot in the presence of ferric salt and hydrogen peroxide to generate the 1, 2-disubstituted olefin. sulfoxide is simultaneously used as a hydrocarbylation reagent and a solvent of olefin, and a reaction product is 1, 2-disubstituted olefin of which a terminal carbon atom in terminal olefin is coupled with a sulfoxide alkyl group, so that an olefin carbon chain is increased; the reaction conditionsare mild, the selectivity is high, the yield is high, and industrial production is facilitated.
Method for synthesizing alkyl olefin through coupling of double-bond carbon-hydrogen bond and saturated carbon-hydrogen bond
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Paragraph 0074-0077; 0106, (2021/02/10)
The invention discloses a method for synthesizing alkyl olefin through coupling of a double-bond carbon-hydrogen bond and a saturated carbon-hydrogen bond. According to to the method, one-pot reactionis implemented on olefin and sulfoxide in the presence of ferric salt and hydrogen peroxide to generate alkyl olefin; in the method, sulfoxide is simultaneously used as a hydrocarbylation reagent anda solvent of olefin, and a reaction product is alkyl olefin from sulfoxide alkyl coupled with olefin carbon atoms, so that an olefin carbon chain is increased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
Enzymatic Primary Amination of Benzylic and Allylic C(sp3)-H Bonds
Jia, Zhi-Jun,Gao, Shilong,Arnold, Frances H.
supporting information, p. 10279 - 10283 (2020/07/27)
Aliphatic primary amines are prevalent in natural products, pharmaceuticals, and functional materials. While a plethora of processes are reported for their synthesis, methods that directly install a free amine group into C(sp3)-H bonds remain unprecedented. Here, we report a set of new-to-nature enzymes that catalyze the direct primary amination of C(sp3)-H bonds with excellent chemo-, regio-, and enantioselectivity, using a readily available hydroxylamine derivative as the nitrogen source. Directed evolution of genetically encoded cytochrome P411 enzymes (P450s whose Cys axial ligand to the heme iron has been replaced with Ser) generated variants that selectively functionalize benzylic and allylic C-H bonds, affording a broad scope of enantioenriched primary amines. This biocatalytic process is efficient and selective (up to 3930 TTN and 96percent ee), and can be performed on preparative scale.
Copper catalyzed enantioselective allylic substitution by MeMgX
Tissot-Croset, Karine,Alexakis, Alexandre
, p. 7375 - 7378 (2007/10/03)
Methyl Grignard undergoes highly regio (>90/10) and enantioselective (ee 91-96%) copper catalyzed allylic substitution on cinnamyl-type chlorides. CuBr (3%) and 3.3% of a chiral phosphoramidite ligand are sufficient for a complete reaction. The synthesis of a precursor of (+)-Naproxen is described. The reaction can be extended to alkyl substituted allylic chlorides (ee 72%).
Reactions of polymer-supported α-selenoaldehydes with Grignard regents. A facile solid-phase stereoselective synthesis of (E)-1,2-disubstituted ethenes
Sheng, Shou-Ri,Huang, Xian
, p. 893 - 896 (2007/10/03)
Polymer-supported α-selenoaldehydes easily obtained by reaction of polymer-supported 4-(phenyl-seleno)morpholine with aldehydes react with Grignard reagents to form polymer-supported β-hydroxyalkyl selenides, which were treated with thionyl chloride/triethylamine leading to (E)-1,2-disubstituted ethenes in good yields.
Novel synthesis of alkenes via triethylborane-induced free-radical reactions of alkyl iodides and β-nitrostyrenes
Liu,Jang,Shih,Hu,Chu,Yao
, p. 6021 - 6028 (2007/10/03)
Reactions of (E)-β-nitrostyrenes 1 and triethylborane 2 or tricyclohexylborane 4 in THF solution at room temperature in the presence of oxygen in the air as radical initiator generate high yields of trans-alkenes (E)-3 or (E)-5. Medium to high yields of d
One-pot synthesis of trans-β-alkylstyrenes
Liu, Ju-Tsung,Yao, Ching-Fa
, p. 6147 - 6150 (2007/10/03)
One-pot synthesis of (E)-alkenes 5 from the reactions of aldehyde 1 and nitromethane 2 in the acetic acid solution and then with triethylborane 4 in the biphase of diethyl ether and aqueous solution in the presence of oxygen in air was reported. Various (E)-alkenes 7 could also be prepared when different kinds of secondary or tertiary alkyl iodides 6 were used under similar conditions.
THE REACTION OF BENZYLIC ALCOHOLS WITH CHLOROTRIMETHYLSILANE/DIMETHYL SULPHOXIDE
Bellesia, Franco,Ghelfi, Franco,Pagnoni, Ugo Maria,Pinetti, Adriano
, p. 437 - 439 (2007/10/02)
With catalytic amounts of chlorotrimethylsilane/dimethyl sulphoxide (CTMSO/DMSO) in acetonitrile benzylic alcohols have been found to give high yields of styrenes.By using stoicheiometric amounts of reagents, different reaction pathways are observed: an elimination-addition sequence occurs with secondary and tertiary alcohols affording vicinal dichloro derivatives, β-chloro thioethers and allyl chlorides, whereas a nucleophilic substitution to the corresponding monochlorides occurs starting from primary and sterically hindered substrates.
Reaction of 1-Aryl-3-chloropropenes with Grignard Reagents. Nucleophilic Substitution versus Single-electron Transfer
Muraoka, Kiyoshige,Nojima, Masatomo,Kusabayashi, Shigekazu,Nagase, Shigeru
, p. 761 - 768 (2007/10/02)
The reactions of ambident 1-aryl-3-chloropropenes (1a-e) with a series of Grignard reagents, R'MgY (R' = Me, Pr, Ph, Pri, But; Y = Br, I), were carried out in diethyl ether (EE) and tetrahydrofuran (THF).The products were a mixture of two alkylation products (2) and (3), and three dimerization products (4)-(6).The alkylation:dimerization ratio and the composition of the two alkylation products were a marked function of substituent electronic effects in the chlorides (1a-e), R' or Y of R'MgY, and solvent.On the basis of the stereochemistry of alkylation, cyclizable probe experiments, and the effect of the addition of FeCl3 on product composition, the following conclusions were obtained.First, dimers (4)-(6) are most likely to be produced by a mechanism involving single-electron transfer (SET).Second, for the formation of alkylation products (2) and (3), three alternative pathways contribute depending on the nature of R'MgY and solvent, (a) competitive SN2-SN2' pathways in the reaction of R'MgBr in EE, (b) a process involving SET in the reaction with R'MgI in EE, and (c) SN2 pathways in the reaction of R'MgBr in THF.
