Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 °C, 2 h) with a ligand-free catalyst (1-2 mol%).

We present here the synthesis and antidepressant-like action of a series of 2,5-disubstituted-3-(organoseleno)-selenophenes prepared by a novel synthetic route, the FeCl(3)-diorganyl dichalcogenide-mediated intramolecular cyclization of (Z)-chalcogenoenynes. The cyclized products were obtained in good yields. The results showed that 2c, 2d, 2e and 2o, evaluated in the mouse forced-swimming test, elicited an antidepressant-like activity. The studies clearly show that the phenyl group at the 2-position and an organoselenium group at the 3-position of the selenophene ring are essential for the antidepressant-like activity of selenophenes. A close inspection of the results also revealed that the fluorophenyl portion in the organoselenium group is fundamental for the antidepressant-like action of this class of organochalcogens.

We reported herein the regio- and stereoselective palladium-catalyzed cross-coupling reactions of unsaturated organoselenides with Sonogashira, Suzuki, Negishi and Kumada partners. The reactions were in general carried out with Pd(PPh3)4 (10 mol%), in DMF at 80 °C to afford the cross-coupling products in good yields. This strategy tolerated a wide range of substrates, such as alkynyl, vinyl, aryl and heteroaryl selenides with a variety of sensitive functional groups and gave the cross-coupling products in good yields.

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These findings suggest a modulation of both serotonergic and glutamatergic systems by F-DPS after a long-term corticosterone exposure in mice, which may be involved in the antidepressant- and anxiolytic-like actions of this organoselenium compound.

A copper-catalyzed cyclization of (ortho-alkynyl)benzaldimines with diorganoyl dichalcogenides allowed the synthesis of 4-organochalcogen isoquinolines, whereas the presence of base in the reaction medium inhibited the product formation producing the undesirable isoquinoline without the organochalcogen atom at the 4-position. The cyclization reaction was carried out by using CuI (20 %) as a catalyst with diorganoyl dichalcogenides (1.5 equiv) in the presence of DMF at 100 °C. Furthermore, the reaction did not require an argon atmosphere and was carried out in an open flask. The cyclization reaction tolerated a variety of functional groups both in ortho-alkynylbenzaldimines and diorganoyl dichalcogenides, such as trifluoromethyl, chloro, fluorine, and methoxyl, to give the six-membered heterocyclic ring exclusively through a 6-endo-dig cyclization process. The organochalcogen group present at the 4-position of the isoquinoline ring was further subjected to a selective chalcogen-lithium exchange reaction followed by the addition of aldehydes to afford the desired secondary alcohols in good yields. The obtained isoquinolines also proved to be suitable substrates for the Suzuki and Sonogashira coupling conditions affording the corresponding products through C-C bond formation.

We have described the application of iron(III) chloride and diorganyl diselenides as cooperative partners in the cyclization of (2‐aminoaryl)‐2‐ynols for the regioselective synthesis of 3‐organoseleno quinolines. The optimized reaction conditions were applied to (2‐aminoaryl)‐2‐ynols that contain a wide range of functional groups, including electron‐rich and electron‐poor substituents. The reaction showed regioselectivity for six‐membered quinoline products, which were formed by a 6‐endo‐dig ring closure, instead of a 5‐exo‐dig process for the formation of indole products. In addition, we also found that (2‐aminoaryl)‐2‐ynols and a catalytic amount of iron(III) chloride, in the absence of diorganyl diselenides, afforded the corresponding quinoline derivatives without the organoseleno moiety at the 3‐position.

Isoquinolines are formed endogenously as metabolites of neurotransmitters and are studied because they have structures similar to neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and selegiline, a selective inhibitor of MAO-B. This study investigated a possible in vitro inhibitory activity of new 4-organochalcogen-isoquinoline derivatives, containing sulfur 1, selenium 2 or tellurium 3 on MAO-A and B activities. Considering that the non-substituted selenoisoquinoline derivative 2 showed the best inhibitory profile (IC50 = 36.45 μM), new compounds were synthesized by adding substituents (methyl 2a, fluorine 2b, chloro 2c and trifluoromethyl 2d) to the aromatic ring bonded to the selenium atom of compound 2. All tested compounds were selective MAO-B inhibitors, although only the substituted isoquinoline derivative 2b showed IC50 lower than the concentration of 100 μM (IC50 = 82.41 μM). Compounds 2 and 2b were chosen to study the inhibitory profile. These compounds demonstrated reversible and mixed inhibition by decreasing apparent V (app) max and increasing apparent K (app) m, however the non-substituted compound 2 was a more potent inhibitor than the substituted compound 2b (K i = 7.07 and 16.30 μM). In conclusion, selenoisoquinolines 2 and 2b fit in the profile of third generation MAO inhibitors (selective and reversible), which are promising alternatives for treatment of emotional and neurodegenerative disorders.