37428-55-0Relevant academic research and scientific papers
Borylation and rearrangement of alkynyloxiranes: A stereospecific route to substituted α-enynes
Fuentespina, Ruben Pomar,De La Cruz, José Angel Garcia,Durin, Gabriel,Mamane, Victor,Weibel, Jean-Marc,Pale, Patrick
supporting information, p. 1416 - 1424 (2019/07/10)
1,3-Enynes are important building blocks in organic synthesis and also constitute the key motif in various bioactive natural products and functional materials. However, synthetic approaches to stereodefined substituted 1,3-enynes remain a challenge, as they are limited to Wittig and cross-coupling reactions. Herein, stereodefined 1,3-enynes, including tetrasubstituted ones, were straightforwardly synthesized from cis or trans-alkynylated oxiranes in good to excellent yields by a one-pot cascade process. The procedure relies on oxirane deprotonation, borylation and a stereospecific rearrangement of the so-formed alkynyloxiranyl borates. This stereospecific process overall transfers the cis or trans-stereochemistry of the starting alkynyloxiranes to the resulting 1,3-enynes.
Intramolecular Diels-Alder Reactions of Tethered Enoate Substituted Furans Induced by Dialkylaluminum Chloride
Riedel, Sibylle,Maichle-M?ssmer, C?cilia,Maier, Martin E.
, p. 12798 - 12805 (2017/12/08)
Gold(I)-catalyzed cycloisomerization of enynols 11 and 17, obtained by Sonogashira coupling, led to the tethered enoate-substituted furans 14 and 19. While attempts at thermal and several Lewis acid induced intramolecular Diels-Alder reactions remained fr
Engaging Alkenyl Halides with Alkylsilicates via Photoredox Dual Catalysis
Patel, Niki R.,Kelly, Christopher B.,Jouffroy, Matthieu,Molander, Gary A.
supporting information, p. 764 - 767 (2016/03/01)
Single-electron transmetalation via photoredox/nickel dual catalysis provides the opportunity for the construction of Csp3-Csp2 bonds through the transfer of alkyl radicals under very mild reaction conditions. A general procedure for the cross-coupling of primary and secondary (bis-catecholato)alkylsilicates with alkenyl halides is presented. The developed method allows not only alkenyl bromides and iodides but also previously underexplored alkenyl chlorides to be employed. (Chemical Equation Presented).
Rhodium-Catalyzed Oxidative C-H Allylation of Benzamides with 1,3-Dienes by Allyl-to-Allyl 1,4-Rh(III) Migration
Korkis, Stamatis E.,Burns, David J.,Lam, Hon Wai
supporting information, p. 12252 - 12257 (2016/09/28)
The Rh(III)-catalyzed oxidative C-H allylation of N-acetylbenzamides with 1,3-dienes is described. The presence of allylic hydrogens cis to the less substituted alkene of the 1,3-diene is important for the success of these reactions. With the assistance of reactions using deuterated 1,3-dienes, a proposed mechanism is provided. The key step is postulated to be the first reported examples of allyl-to-allyl 1,4-Rh(III) migration.
3-Chloro-1-lithiopropene, a functional organolithium reagent, and its reactions with alkylboronates to give 3-alkylprop-1-en-3-ols
Smith, Keith,Elliott, Mark C.,Jones, D. Heulyn
, p. 9526 - 9531 (2013/10/08)
The reagent 3-chloro-1-lithiopropene (4) can be generated by treating 1-bromo-3-chloropropene with t-BuLi. It is unstable but if generated at low temperature in the presence of alkylboronic esters, such as 3, is trapped in situ to give rearrangement products 2, which on oxidation give 3-alkylprop-1-en-3-ols in good yields. The reaction works for primary, secondary, benzylic, and even tertiary alkylboronic esters, providing allylic alcohols bearing almost any alkyl group available using organoborane chemistry and incorporating all features of such groups.
Stereocontrolled synthesis of a Cn-Cn+7 building block ("eastern moiety") for the unnatural enantiomers of important polyol,polyene antibiotics based on a ring-closing metathesis and an aldol addition of a lactone enolate
Kamptmann, Sonja B.,Brueckner, Reinhard
, p. 6584 - 6600 (2013/11/06)
A stereocontrolled synthesis of epoxide 6, which represents the C n-Cn+7 or "eastern moiety" building block for the title compounds, has been realized in 19 steps. Our synthesis started from tetrabromoacetone 26 and afforded dibromotriene 33b in six steps. The latter was subjected to a ring-closing metathesis, which gave the dibromovinyl-substituted lactone 34 in high yield. A highly stereoselective conjugate addition/enolate aldolization sequence established the additional stereocenters with perfect selectivity. Epoxide 47b was reached in another eight steps, which included a C-SiMe2Pha€‰→a€‰C-OH oxidation in the presence of an acetal group. The final structure 6 was completed by hydrostannylation/brominolysis. A dibromovinyl-substituted unsaturated δ-lactone obtained by ring-closing metathesis underwent a highly diastereoselective silyl cuprate 1,4-addition/aldolization sequence. Tamao-Fleming oxidation transformed the silyl into a hydroxy group. Alkyne formation, hydrostannylation, and N-bromosuccinimidolysis converted the dibromovinyl into a trans-bromovinyl moiety. Copyright
Palladium-catalyzed intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides
Shen, Zengming,Ni, Zhenjie,Mo, Song,Wang, Jing,Zhu, Yamin
supporting information; experimental part, p. 4859 - 4865 (2012/06/04)
Give me a ring? An efficient approach has been developed for the intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides catalyzed by palladium (see scheme). From a synthetic viewpoint, this method is highly attractive because the catalyst loading is low, the optimized reaction conditions are mild, and the substrate scope is broad. Copyright
Synthesis of γ-functionalized allyltrichlorosilanes and their application in the asymmetric allylation of aldehydes
Malkov, Andrei V.,MacDonald, Claire,Koovsky, Pavel
scheme or table, p. 1173 - 1175 (2010/11/02)
Isomerically pure trans-and cis-γ-bromoallyltrichlorosilanes 4 and 5 have been synthesized and shown to react with aromatic aldehydes 1 in the presence of Lewis-basic catalysts (e.g., DMF) to produce the corresponding anti-and syn-allylbromohydrins 8 and 9, respectively, as single diastereoisomers. With BINAPO 25 as a chiral catalyst, promising enantioselectivity (≤50% ee) has been attained.
Asymmetric synthesis of both enantiomers of anti-4,4,4-trifluorothreonine and 2-amino-4,4,4-trifluorobutanoic acid
Jiang, Zhong-Xing,Qin, Ying-Ying,Qing, Feng-Ling
, p. 7544 - 7547 (2007/10/03)
A short and efficient enantio selective synthesis of both enantiomers of anti-4,4,4-trifluorothreonine and 2-amino-4,4,4-trifluorobutanoic acid was successfully developed. Trifluoromethylation of benzyl-protected bromoalkene 4 provided key intermediate trifluoromethylated transdi-substituted alkene 2 in good yield. The sequence then involved Sharpless asymmetric dihydroxylation, nucleophilic opening of cyclic sulfate with NaN3, palladium-catalyzed selective hydrogenation, and oxidation.
A highly efficient, selective, and general method for the synthesis of conjugated (all-E)-oligoenes of the (CH=CH)n type via iterative hydrozirconation-palladium-catalyzed cross-coupling
Zeng, Fanxing,Negishi, Ei-Ichi
, p. 703 - 706 (2007/10/03)
(equation presented) A linear iterative method for the construction of (all-E)-oligoenes of the (CH=CH)n type via hydrozirconation-palladium-catalyzed cross-coupling with (E)-1-bromo-4-trimethylsilyl-1-buten-3-yne is described. This method promises to provide an efficient, selective, and general route to oligoene macrolide antibiotics and other related natural products.
