63667-83-4Relevant academic research and scientific papers
Access to Trisubstituted Fluoroalkenes by Ruthenium-Catalyzed Cross-Metathesis
Nouaille, Augustin,Pannecoucke, Xavier,Poisson, Thomas,Couve-Bonnaire, Samuel
, p. 2140 - 2147 (2021/03/06)
Although the olefin metathesis reaction is a well-known and powerful strategy to get alkenes, this reaction remained highly challenging with fluororalkenes, especially the Cross-Metathesis (CM) process. Our thought was to find an easy accessible, convenient, reactive and post-functionalizable source of fluoroalkene, that we found as the methyl 2-fluoroacrylate. We reported herein the efficient ruthenium-catalyzed CM reaction of various terminal and internal alkenes with methyl 2-fluoroacrylate giving access, for the first time, to trisubstituted fluoroalkenes stereoselectively. Unprecedent TON for CM involving fluoroalkene, up to 175, have been obtained and the reaction proved to be tolerant and effective with a large range of olefin partners giving fair to high yields in metathesis products. (Figure presented.).
Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
Lu, Yanhui,Nakatsuji, Hidefumi,Okumura, Yukimasa,Yao, Lu,Ishihara, Kazuaki
, p. 6039 - 6043 (2018/05/14)
Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol, α-Tocotrienol, Daedalin A and Englitazone in short steps. Furthermore, a halogenated product with an unsaturated side chain may provide polycyclic adducts under radical cyclization conditions.
Scandium as a pre-catalyst for the deoxygenative allylation of benzylic alcohols
?oli?, Ivan,Seankongsuk, Pattarakiat,Loh, Joanna Kejun,Vilaivan, Tirayut,Bates, Roderick W.
supporting information, p. 119 - 123 (2017/12/27)
Scandium triflate is an effective pre-catalyst for the deoxygenative allylation of benzylic alcohols with a narrow substrate window. The reaction is shown to proceed through a "hidden Br?nsted acid" mechanism. The reaction is efficient provided that the aryl group is neither too electron rich nor too electron poor. It is shown that this allows useful selectivity. The reaction also works for benzyhydryl alcohols with broader scope. The reaction may also be catalysed by Nafion.
Synthesis of Chiral 1,4-Benzodioxanes and Chromans by Enantioselective Palladium-Catalyzed Alkene Aryloxyarylation Reactions
Hu, Naifu,Li, Ke,Wang, Zheng,Tang, Wenjun
, p. 5044 - 5048 (2016/04/26)
A highly enantioselective alkene aryloxyarylation led to the high-yielding formation of a series of 1,4-benzodioxanes, 1,4-benzooxazines, and chromans containing quaternary stereocenters with excellent enantioselectivity. The sterically bulky and conformationally well defined chiral monophosphorus ligand L4 or L5 was responsible for the high reactivity and enantioselectivity of these transformations. The application of this method to the synthesis of the chiral chroman backbone of α-tocopherol was demonstrated. One P is plenty: A sterically bulky and conformationally well defined chiral monophosphorus ligand enabled the highly enantioselective synthesis of a series of Oheterocycles containing a quaternary stereocenter by alkene aryloxyarylation (see scheme; X=O, C, N). The application of this transformation to the synthesis of the chiral chroman backbone of α-tocopherol is demonstrated.
Regioselective cross-coupling of allylindium reagents with activated benzylic bromides-a simple and efficient procedure for the synthesis of terminal alkenes
Ranu, Brindaban C.,Banerjee, Subhash,Adak, Laksmikanta
, p. 7374 - 7379 (2008/03/13)
Allylindium reagents undergo facile and highly regioselective cross-coupling with benzylic and cinnamyl bromides in THF at room temperature without any catalyst producing terminal alkenes in high yields. The addition is highly regioselective and is found to provide γ-adducts in all reactions.
Selective Cross Coupling via Oxovanadium(V)-Induced Oxidative Desilylation of Benzylic Silanes
Hirao, Toshikazu,Fujii, Takashi,Ohshiro, Yoshiki
, p. 8005 - 8008 (2007/10/02)
Benzylic silanes bearing an electron-donating group at the ortho- or para-position underwent the oxovanadium(V)-induced one-electron oxidative desilylation due to low ionization potential, which was applied to the intermolecular regioselective coupling with allylic silanes or silyl enol ether.
Tandem Wessely oxidation and intramolecular Diels-Alder reactions. III. Synthesis of isotwistanes
Yates, Peter,Macas, Tadas S.
, p. 1 - 10 (2007/10/02)
Wessely oxidation of o-(3-alkenyl) phenols (5) with lead tetraacetate gives 6-acetoxy-6-(3-alkenyl)-2,4-cyclohexadien-1-ones (6), which undergo intramolecular Diels-Alder reactions to give isotwistene (hexahydro-1,5-methanoindene) derivatives (7).These, on hydrolysis followed by oxidation with periodic acid, give hexahydro-1-oxo-1H-indene-5-carboxylic acids (41, 46).Compounds 5 were prepared either by Grignard coupling of o-methoxybenzyl chloride with allyl halides followed by de-O-methylation with sodium thioethoxide or via reduction of dihydrocoumarins (18-20) to 2-chromanols (21-23) with diisobutylaluminum hydride, followed by Wittig reaction of these with ethyl (triphenylphosphoranylidene)acetate.
β-Adrenergic blocking agents: Substituted phenylalkanolamines. Effect of side-chain length on β-blocking potency in vitro
Fuhrer,Ostermayer,Zimmermann,Meier,Mueller
, p. 831 - 836 (2007/10/02)
The synthesis of a group of potential β-blockers bearing a new 5-ethoxysalicylamide substituent on nitrogen is described. These compounds were tested for β-adrenergic blocking potency in vitro and compared with analogous compounds bearing a tert-butyl group on nitrogen. The new N-substituent increased the β-blocking potency substantially. In a series of five homologous compounds of the type Ar(CH2)(n)CHOHCH2NHR (R = 5-ethoxysalicylamide; n = 0-4), two maxima of β-blocking potency were found for n = 0 and 2. Moreover, the carbon isostere of the corresponding (aryloxy)propanolamine still proved to be a very potent β-blocker. The ether oxygen in the side chain is therefore not an absolute requirement for activity. Structure-activity relationships are discussed.
