Iron-catalyzed coupling reactions of vinylic chalcogenides with Grignard reagents

Abstract

Este trabalho descreve um novo método para a reação de acoplamento entre selenetos e teluretos vinílicos e reagentes de Grignard, catalisada por Fe(acac) 3 e à temperatura ambiente. A reação ocorre com retenção da configuração, fornecendo os respectivos alquenos em bons a excelentes rendimentos. Este método também é eficiente para a reação de acoplamento de calcogenetos bisvinílicos com reagentes de Grignard.A general new method for the cross-coupling reaction between vinylic selenides and tellurides and Grignard reagents catalyzed by Fe(acac) 3 at room temperature is described. This reaction proceeded with retention of configuration, providing the respective alkenes in good to excellent yields. This method is also efficient for the coupling reaction of divinyl chalcogenides with Grignard reagents. Keywords: iron-catalyzed, vinylic chalcogenides, cross-coupling, Grignard reagents IntroductionOrganochalcogenium compounds became the key component of a variety of versatile and useful reagents for organic synthesis. The multiple applications of organochalcogenium chemistry have been well described in a number of review articles 1-6 and books. 7-11 Functionalized alkynyl 12-18 and alkenyl [19][20][21][22][23] chalcogenides have a great potential in organic synthesis, since they are valuable intermediates for the selective preparation of several organic compounds.Among the many applications of vinylic selenides, divinylic selenides and vinylic sulfides, the cross-coupling reaction with Grignard reagents catalyzed by Ni 18,24-27 and Pd 28,29 to give the corresponding cross-coupled products, has been described. On the other hand, Pd 19,30 and Ni 24,[31][32][33] catalyzed cross coupling reactions and tellurium/metal exchange reactions [34][35][36][37][38][39][40][41][42] are demonstrative of the usefulness of vinylic tellurides.Transition-metal-catalyzed C-C bond coupling reactions are very important in many areas of science. 43,44 Most current methods require expensive transitionmetal catalysts and ligands. However, in the last years Fe-catalyzed C-C bond cross coupling reactions of vinylic substrates and Grignard reagents became a subject of intense interest. [45][46][47][48][49][50][51] The vinylic counterpart is quite broad in scope, since vinylic halides, triflates, sulfonates, tosylates and enol phosphates can be used. [45][46][47][48][49][50][51] In continuation to our interest on the synthesis and synthetic applications of vinylic chalcogenides 52-58 we decided to study the feasibility of their use in cross coupling reaction with Grignard species catalyzed by iron. To the best of our knowledge, iron catalysts have never been used for the coupling of vinylic selenides and tellurides as electrophiles. The possible use of iron catalysts would represent a great improvement over the high cost of palladium precursors and from the concerns about the toxicity of nickel salts. In light of the above comments it is of interest to design a simple, efficient, and versatile method for the stereoselective coupling of vinylic se...

Iron Catalysis in Organic Synthesis

“…303 It is noteworthy that the somewhat exotic vinyl selenides and tellurides are even better electrophiles for the iron-catalyzed cross coupling with alkyl-and arylmagnesium bromides (Scheme 142). 304 This reaction was reported to proceed with retention of configuration affording the substituted alkenes in high yields. 305 They required an ortho-imino group as activating function and obtained ortho-substituted benzaldehydes after acidic hydrolysis.…”

Selenium Dihalides Click Chemistry: Highly Efficient Stereoselective Addition to Alkynes and Evaluation of Glutathione Peroxidase-Like Activity of Bis(E-2-halovinyl) Selenides

“…Vinyl selenides are versatile intermediates and synthons for organic synthesis. A series of valuable products, including functionalized alkenes, ketones, ( Z )-allyl alcohols, unsaturated aldehydes, and enyne derivatives, were obtained based on vinyl selenides [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ].…”

(Z,Z)-Selanediylbis(2-propenamides): Novel Class of Organoselenium Compounds with High Glutathione Peroxidase-Like Activity. Regio- and Stereoselective Reaction of Sodium Selenide with 3-Trimethylsilyl-2-propynamides

“…Vinyl selenides are important intermediates for organic synthesis [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. These compounds have been used for the preparation of a number of valuable products [ 4 , 5 , 6 , 7 , 8 , 9 ]. Vinyl selenides have found application in the synthesis of functionalized ketones, ( Z )-allyl alcohols, and unsaturated aldehydes [ 4 ].…”

“…The cross-coupling of vinyl selenides with terminal alkynes in the presence of a nickel/CuI catalyst at room temperature proceeded with of retention of stereochemical configuration leading to ( Z )- and ( E )-enyne derivatives in good yields [ 5 ]. The coupling reaction of vinyl selenides with Grignard reagents provided corresponding functionalized alkenes [ 6 , 7 ]. The synthesis of resveratrol and its methoxylated analogues—well known compounds due to their anti-inflammatory, anticancer, antibacterial, and neuroprotective activity, has been proposed based on vinyl selenides [ 8 ].…”