63798-14-1Relevant articles and documents
Electroreductive Carbofunctionalization of Alkenes with Alkyl Bromides via a Radical-Polar Crossover Mechanism
Zhang, Wen,Lin, Song
supporting information, p. 20661 - 20670 (2020/12/23)
Electrochemistry grants direct access to reactive intermediates (radicals and ions) in a controlled fashion toward selective organic transformations. This feature has been demonstrated in a variety of alkene functionalization reactions, most of which proceed via an anodic oxidation pathway. In this report, we further expand the scope of electrochemistry to the reductive functionalization of alkenes. In particular, the strategic choice of reagents and reaction conditions enabled a radical-polar crossover pathway wherein two distinct electrophiles can be added across an alkene in a highly chemo- and regioselective fashion. Specifically, we used this strategy in the intermolecular carboformylation, anti-Markovnikov hydroalkylation, and carbocarboxylation of alkenes - reactions with rare precedents in the literature - by means of the electroreductive generation of alkyl radical and carbanion intermediates. These reactions employ readily available starting materials (alkyl halides, alkenes, etc.) and simple, transition-metal-free conditions and display broad substrate scope and good tolerance of functional groups. A uniform protocol can be used to achieve all three transformations by simply altering the reaction medium. This development provides a new avenue for constructing Csp3-Csp3 bonds.
Enantiospecific Solvolytic Functionalization of Bromochlorides
Burckle, Alexander J.,Gál, Bálint,Seidl, Frederick J.,Vasilev, Vasil H.,Burns, Noah Z.
supporting information, p. 13562 - 13569 (2017/10/05)
Herein, we report that under mild solvolytic conditions, enantioenriched bromochlorides can be ionized, stereospecifically cyclized to an array of complex bromocyclic scaffolds, or intermolecularly trapped by exogenous nucleophiles. Mechanistic investigations support an ionic mechanism wherein the bromochloride serves as an enantioenriched bromonium surrogate. Several natural product-relevant motifs are accessed in enantioenriched form for the first time with high levels of stereocontrol, and this technology is applied to the scalable synthesis of a polycyclic brominated natural product. Arrays of nucleophiles including olefins, alkynes, heterocycles, and epoxides are competent traps in the bromonium-induced cyclizations, leading to the formation of enantioenriched mono-, bi-, and tricyclic products. This strategy is further amenable to intermolecular coupling between cinnamyl bromochlorides and a diverse set of commercially available nucleophiles. Collectively, this work demonstrates that enantioenriched bromonium chlorides are configurationally stable under solvolytic conditions in the presence of a variety of functional groups.
Alkylboronic esters from palladium- and nickel-catalyzed borylation of primary and secondary alkyl bromides
Yi, Jun,Liu, Jin-Hui,Liang, Jun,Dai, Jian-Jun,Yang, Chu-Ting,Fu, Yao,Liu, Lei
supporting information; experimental part, p. 1685 - 1691 (2012/07/28)
Palladium- and nickel-catalyzed cross-coupling recations of unactivated alkyl bromides with diboron reagents have been developed as practical methods for the synthesis of primary and secondary alkylboronic esters. These reactions extend the concept and utility of Pd- and Ni-catalyzed cross-coupling of aliphatic electrophiles. They also show different substrate selectivity and ligand dependence as compared to the recently reported Cu-catalyzed borylation reaction. Copyright
Iron(III)-catalyzed halogenations by substitution of sulfonate esters
Ortega, Nuria,Feher-Voelger, Andres,Brovetto, Margarita,Padron, Juan I.,Martin, Victor S.,Martin, Tomas
, p. 963 - 972 (2011/06/20)
A novel halogenation reaction from sulfonates catalyzed by iron(III) is described. The reaction can be performed as a stoichiometric or a catalytic version. This reaction provides a convenient strategy for the efficient access to structurally diverse secondary chlorides, bromides and iodides. The stereochemical course of the reaction is governed by the substrate and the experimental conditions. Secondary alcohols modified as quisylates or pysylates are substantially more reactive. Aliphatic quisylates proceed with overall inversion of configuration under catalytic conditions. Chemoselectivity in bismesylates was observed in favour of the secondary mesylate. Additionally, based on the experimental results, a possible catalytic cycle for the halogenation has been proposed.
Enantioselectivity of haloalkane dehalogenases and its modulation by surface loop engineering
Prokop, Zbynek,Sato, Yukari,Brezovsky, Jan,Mozga, Tomas,Chaloupkova, Radka,Koudelakova, Tana,Jerabek, Petr,Stepankova, Veronika,Natsume, Ryo,Van Leeuwen, Jan G. E.,Janssen, Dick B.,Florian, Jan,Nagata, Yuji,Senda, Toshiya,Damborsky, Jiri
supporting information; experimental part, p. 6111 - 6115 (2010/11/05)
In the loop: Engineering of the surface loop in haloalkane dehalogenases affects their enantiodiscrimination behavior. The temperature dependence of the enantioselectivity (lnE versus 1/T) of β-bromoalkanes by haloalkane dehalogenases is reversed (red data points) by deletion of the surface loop; the selectivity switches back when an additional single-point mutation is made. This behavior is not observed for -bromoesters.
Nucleophilic substitution of 1-phenyl-2-phenyl telluropropane to yield 2-halo-1-phenylpropanes
Ogura, Fumio,Okada, Yoshiharu,Nishimura, Naoko,Hamamoto, Kenichiro,Miyakawa, Makoto,Otsubo, Tetsuo,Aso, Yoshio,Inoue, Shinobu,Tsutsui, Koji
, p. 203 - 210 (2007/10/03)
Mechanism of a novel transformation of the alkyl phenyltellurides to alkyl halides via nucleophilic substitution of the phenyltelluro group in organotelluriums is studied on the basis of kinetics and stereochemistry using the titled chiral substrate. The results obtained strongly suggest that the substitutions proceed via SN2 mechanism with Walden inversion and very low Arrhenius' energies of activation.
