Elizabeth S. Balenkova

Preparation of α, β-Unsaturated Ketones Bearing a Trifluoromethyl Group and Their Application in Organic Synthesis

, Andrei V. Sanin, Elizabeth S. BalenkovaDepartment of Chemistry, Moscow State University, 119899 Moscow, RussiaTel.: +7 (095) 939-43-94; Fax: +7 (095) 932-88-46; E-mail: Nen@acylium.chem.msu.suReceived: 9 December 1996 / Accepted: 28 March 1997 / Published: 1 December 1997Abstract: The approaches to the synthesis of α,β-unsaturated CF

3‐Trifloxy‐3‐trifluoromethylpropeniminium Triflate: Reaction with Aromatic Amines – An Efficient Synthesis of 2‐Trifluoromethylquinolines

The reaction of iminium triflates 2 and 7 with various aromatic amines were investigated. The 2-Rf-substituted quinolines 3 and 8 were prepared in excellent yields by the reaction of 2 and 7, respectively, with substituted anilines. The reactions of 2 and 7 with diarylamines proceeds, suprisingly, to afford the corresponding 3-Rf-substituted cinnamaldehydes 4 and 9.

Novel efficient synthesis of dibromoalkenes. A first example of catalytic olefination of aliphatic carbonyl compounds

A new simple and efficient one pot transformation of various aliphatic carbonyl compounds to the corresponding dibromoalkenes is described. A wide range of hydrazones of aldehydes and ketones, prepared in situ, were easily converted into dibromoalkenes by treatment with carbon tetrabromide in the presence of CuCl. The reaction proceeds under mild conditions to give the target products in good to high yields.

Two Modifications Formed by "Sulflower" C16S8 Molecules, Their Study by XRD and Optical Spectroscopy (Raman, IR, UV-Vis) Methods

Sublimation of sulflower, octathio[8]circulene C 16S 8 ( 1), on heating under high vacuum ( approximately 10 (-5) Torr) leads to successive formation of two modifications: a white film ( 1W) and a red polycrystalline solid ( 1R). When kept at room temperature for several weeks, 1W spontaneously turns pink, reflecting the monotropic phase transition 1W --> 1R. The accurate molecular and crystal structure of 1R has been studied using low-temperature (100 K) high-resolution single crystal X-ray analysis. The C 16S 8 molecule in crystal is strictly planar with nearly equalized bonds of each type (C-C, C-S, and CC). The point symmetry group of the free molecule is D 8 h , and the crystal space group is P2 1/ n. These data allowed group-theoretical analysis of vibrational normal modes to be accomplished. Investigation of the charge density distribution of 1R including Baders AIM approach has revealed rather strong intermolecular S...S, S...C, and C...C interactions of charge transfer and pi-stacking types with overall lattice energy of 28.5 kcal/mol. The charge transfer due to the S...S interactions is the reason for the red coloration of 1R. The latter is reflected by its UV-vis spectrum exhibiting absorption bands in the visible region which are absent from that of 1W. Both modifications were studied comparatively by vibrational (Raman, IR) and electronic spectroscopies as well as XRD powder diffraction. All the results obtained are fully consistent and show that 1W is much less ordered than 1R with significantly weakened intermolecular interactions. Rationalizing of these results has led to an idea that 1W could be soluble, in contrast to 1R. Indeed, 1W appeared soluble in common solvents; this finding opens the way to the study of the chemistry of 1 and investigation of its electrooptical properties.

Fragmentation of Trifluoromethylated Alkenes and Acetylenes by N,N-Binucleophiles. Synthesis of Imidazolines or Imidazolidines (Oxazolidines) Controlled by Substituent

The reaction of beta-halogeno-beta-polyfluoromethylstyrenes with N,N- or N,O-binucleophiles leads to unexpected fragmentation products (imidazolines) or to heterocyclization giving CF(3)-substituted imidazolidines (N,N-) and oxazolidines (N,O-) depending on aryl substituent. The scope and the reaction mechanism are discussed.

Catalytic olefination of carbonyl compounds. A new versatile method for the synthesis of alkenes

The review is devoted to a new catalytic olefination reaction (COR) discovered by the authors. This is the reaction between N-unsubstituted hydrazones of carbonyl compounds with dihalides CHal2XY in the presence of copper(i) chloride to give substituted alkenes. Catalytic olefination is versatile. Variation of the carbonyl and olefinating components opens up the way for the synthesis of various classes of unsaturated compounds including those containing functional groups. The reaction mechanism is discussed and a catalytic cycle describing the process is proposed. A model for estimating and predicting the reactivity of halogen-containing compounds in the COR is developed. The relationship between the structure of the carbonyl substrates and their behavior in the title reaction is elucidated.

Diels–Alder reactions of β-trifluoroacetylvinylsulfones

Abstract Diels–Alder reactions of β-trifluoroacetylvinylsulfones with 1,3-dienes in CH 2 Cl 2 afforded corresponding mono- and polycycloadducts. A possibility of stereo- and regioselective cycloaddition was investigated. Elimination of sulfonyl group from cycloadducts leads to α,β-unsaturated trifluoromethylketones in good yields.

A facile route to thiophene-1,1-dioxides bearing electron-withdrawing groups

Abstract No commonly available synthetic method for thiophene-1,1-dioxides with strong EWGs has been described to date. Trifluoroperacetic acid in acetonitrile in the absence of water is shown to oxidise thiophenes, including examples possessing an electron-withdrawing group such as sulfonyl or alkoxycarbonyl. An easy and ready for scale-up procedure is developed, some formerly unknown thiophene-1,1-dioxides are obtained.

Perfluoroacylation of alkenes

Reaction of direct electrophilic perfluoroacylation of different structure alkenes with trifluoroacetic anhydride activated by BF3 · SMe2 complex leads to trifluoromethylalkenylketones with different structure of alkenyl group. Possible composition of the reactive species is considered on the basis of IR and NMR data. Dependence of the reaction course on the substrate structure is discussed.

A new convenient approach to chiral β-aryl(heteroaryl)alkylamines

Abstract Chiral β-aryl(heteroaryl)alkylamines have been prepared from N -tosyl alkylaziridines via regiospecific nucleophilic ring opening and subsequent desulfonylation in good to excellent yields. The corresponding aziridines are easily obtained from commercially available ( S )-α-amino acids, so this method is the first effective route to asymmetric β-aryl(heteroaryl)alkylamines.