Olga V. Serdyuk

Non-heme iron catalysts for epoxidation and aziridination reactions of challenging terminal alkenes: towards sustainability

Through catalytic epoxidation and aziridination of olefins versatile synthetic intermediates and subunits of biologically active compounds and pharmaceuticals –epoxides and aziridines– can be obtained. The focus of this review is on recent advances in the epoxidation and aziridination of challenging terminal alkenes with respect to safety of solvents or reagents used and atom economy aspects, as well as scope and limitations of developed non-heme iron catalysts. The still large research potential for sustainable and environmentally attractive iron-based catalysts in enantioselective epoxide and aziridine synthesis is demonstrated.

Chemistry of Fluorinated Indoles

The chapter is devoted to the synthesis and application of indoles as well as some their azaanalogues bearing fluorine atoms, trifluoromethyl groups, and perfluorinated aryl fragments.

Chemistry of Fluorinated Pyrroles

Synthetic approaches towards pyrroles, bearing fluorine atoms and trifluoromethyl group, are overviewed in this chapter. Literature data are surveyed accordingly to reaction type used to obtain the fluorinated pyrrole moiety. Properties as well as some applications of fluorinated are also reviewed.

Simple synthesis of 4-aryl-9-furylnaphtho[2,3-b]furan

Recently, we have shown that 2-[di(2-furyl)methyl]benzhydrols 2 react under conditions of acidic catalysis to give not the expected 4-aryl-9-furyl-4,9-dihydronaphtho[2,3-b]furans, but rather the isomeric 9-aryl4-furyl-4,9-dihydronaphtho[2,3-b]furans 3 [1]. It is known that 9-furylnaphtho[2,3-b]furans can be prepared by an intramolecular, acid-catalyzed condensation of (2-formylaryl)difurylmethanes [2], hence we have proposed that (2-aroylaryl)difurylmethanes should give 4-aryl-9-furylnaphtho[2,3-b]furans in the presence of an acid catalyst. In fact, the workup of compound 5 (obtained by oxidation of the benzhydrol 2) with p-toluenesulfonic acid in benzene gives the naphthofuran 6 in high yield. However, the synthesis of (2-aroylaryl)difurylmethane 5 from the starting formylbenzoic acid 1 involves 5 steps, and this unavoidably leads to a lowering of the overall yield of the product 6. We have developed a simple, one-pot synthesis of the naphthofuran 6 from 2-aroylbenzaldehyde 4 and 2-methylfuran which consists of maintaining the reagents at 70oC in 1,4-dioxane, in the presence of catalytic amounts of perchloric acid. It should be noted that lowering the reaction temperature to 40oC allowed the isolation of the intermediate aryldifurylmethane 5. IR spectra were recorded on a Bruker Alpha FT-IR spectrophotometer in KBr pellets. H and C NMR spectra for compound 5 were recorded on a Bruker DPX-300 spectrometer (300 and 75 MHz, respectively), and for compound 6 on a Bruker Avance-600 spectrometer (600 and 150 MHz, respectively), with the residual proton signals of the solvent as standards (CDCl3 at 7.25 ppm for the H nuclei and at 77.0 ppm for the C nuclei). Mass spectra were obtained on a Kratos MS-30 spectrometer using EI with ionization energy 70 eV and ionization chamber temperature 200oC. Elemental analysis was carried out on a Vario MICRO cube CHNS Analyzer. Melting points for the obtained compounds were determined on a Stuart SMP30 melting point apparatus. Monitoring of the course of the reaction was carried out by TLC on the Sorbpolymer company plates. Purification of the reaction mixtures was performed on KSK grade silica gel (Sorbpolymer, fraction 5-40 μm). Compound 2 was obtained by method [1], and 2-aroylbenzaldehyde 4 was synthesized by method [3]. 2-[Bis(5-methyl-2-furyl)methyl]phenyl-4-methylphenylmethanone (5). Pyridinium chlorochromate (PCC) (3.00 g, 14.0 mmol) was added to a solution of compound 2 (2.00 g, 5.4 mmol) in dry CH2Cl2 (50 ml). ______ *To whom correspondence should be addressed, e-mail: alexander_butin@mail.ru.

Furfuryl aryl(alkyl) ketones: preparation and synthetic potential (review)

Methods for the synthesis of furfuryl aryl(alkyl) ketones, published from 1985 to 2011, have been reviewed. The synthetic potential of these compounds is presented.

Fluorinated Thiophenes and Their Analogues

The chapter is devoted to the synthesis and application of thiophenes (selenophenes) and benzothiophenes bearing fluorine atoms, CF3 groups, and perfluorinated aryl fragments.

Fluorinated Furans and Benzofurans

Synthesis, reactions, and application of furans and benzofurans bearing a fluorine atom and a trifluoromethyl group are reviewed.