Igor I. Gerus

β-Ethoxyvinyl polyfluoroalkyl ketones — versatile synthones in fluoroorganic chemistry

Abstract We have found readily available β-ethoxyvinyl trifluoromethyl ketone to be a convenient and comprehensive starting material for the synthesis of various fluoro-containing compounds such as heterocycles, enones, enaminones and chelate complexes. The 4,4,4-trifluoro-3-oxo-l-butenyl group formed by β-ethoxyvinyl trifluoromethyl ketone is a suitable protecting group for the N-H terminal of amino acids in peptide synthesis. The formation of peptides using these protected amino acids occurs without racemization.

The interaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one with C-nucleophiles : organo-magnesium and -zinc compounds

Abstract 4-Ethoxy-1,1,1-trifluoro-3-buten-2-one ( 1 ) reacts with phenylmagnesium bromide to give ethoxy group substitution products while the reaction of 1 with organozinc compounds gives products arising from 1,2-addition to the carbonyl group. Enone 1 reacts with electron-rich aromatic systems such as indole and N,N -dimethylaniline in the presence of a Lewis acid catalyst to give a β-arylvinyltrifluoromethylketone.

Trifluoromethyl vs. methyl ability to direct enantioselection in microbial reduction of carbonyl substrates.

Abstract The stereoselective reduction of 3-trifluoromethylcyclohexanone ( 1a ), ( E )-1,1,1-trifluoro-4-phenyl-3-buten-2-one ( 3a ), and their unfluorinated analogues 1b and 3b has been performed with some growing microorganisms. Differences in the electronic and steric properties of the trifluoromethyl and methyl residues result in different chemo- and stereoselectivities in the microbial reduction of phenylbutenones 3a and 3b while cyclohexanones 1a and 1b showed strictly similar stereoselectivities. A new protocol based on 13 C NMR spectra of 2-phenylpropionic acid esters has been used to assign the absolute configuration of the obtained secondary alcohols.

Regioselective Addition of Trimethylsilyl Cyanide to β-Alkoxyvinyl Alkyl Ketones

Abstract The 1,2- and 1.4-addition reactions of trimethylsilyl cyanide to alkyl vinyl ketones were studied. Regioselectivity of this reaction depends on the structure of alkyl vinyl ketones, the reaction temperature and the nature of catalyst. The presence of alkoxy group in β-position of α,β-enone is the important condition for realization of 1,4-addition. Ambient temperature (25°C) or base catalyst (NEt3) directed the reaction predominantly into 1,2-addition; higher temperature, electrophilic catalyst (I2) and bulky alkyl substituents near the carbonyl group directed the reaction in 1,4-addition route. Hydrolysis of 1,4-adducts yields saturated fluorine-containing ketones containing CN- and ethoxy groups at the β-position.

Silver(I) and Copper(I) Adducts of a Tris(pyrazolyl)borate Decorated with Nine Trifluoromethyl Groups

Silver and copper ethylene adducts and the silver carbonyl complex of the tris(pyrazolyl)borate [HB(3,4,5-(CF(3))(3)Pz)(3)](-) (which is based on one of the most acidic pyrazoles known) have been synthesized. (13)C NMR resonance signals of metal-bound ethylene carbon atoms of [HB(3,4,5-(CF(3))(3)Pz)(3)]Ag(C(2)H(4)) and [HB(3,4,5-(CF(3))(3)Pz)(3)]Cu(C(2)H(4)) appear at δ 111.6 and 94.9, respectively. The CO stretching frequency of the silver adduct [HB(3,4,5-(CF(3))(3)Pz)(3)]Ag(CO) is significantly higher than that of free CO, but it appears at a region less sensitive to the ligand electronic effects of tris(azolyl)borate silver adducts.

α,β-Unsaturated enamino-ketones with trifluoromethyl groups. Infrared spectra and structure

The infrared spectra of two enamino-ketones containing the trifluoromethyl group, namely, 4-(N-methylamino)- 1 and 4-(N,N-dimethylamino)-1, 1, 1 -trifluorobut-3-en-2-one 2 have been investigated in a number of solvents. It has been shown the title compounds possess spectral characteristics different from those of nonfluorinated analogues. Spatial and electronic structure features of these enamino-ketones are discussed.

Regioselective addition of trimethylsilyl cyanide toE-1,1,1-trifluoro-4-ethoxybut-3-en-2-one

Abstract The 1,2- and 1,4-addition reactions of trimethylsilyl cyanide to 1,1,1-trifluoro-4-ethoxybut-3-en-2-one were studied. The regioselectivity of this reaction depends on the temperature, the nature of solvent and the catalyst: low temperatures or basic catalysts direct in favour of 1,2-addition while high temperatures or acidic catalysts direct in favour of 1,4-addition.

Regioselective reactions of β-aminovinyl trifluoromethyl ketones with tosyl isocyanate

Abstract The NH- and α-CH-insertion reactions of tosyl isocyanate with N-monosubstituted and N,N-disubstituted trifluoromethyl-containing enaminones have been studied. The regioselectivity of N-tosylcarbomoylation of N-monosubstituted β-aminovinyl trifluoromethyl ketones depends on the structure of enaminones, the reaction temperature, the nature of solvent and catalyst. The Z configuration of fluorinated vinylogous sulphonylurea 3e was deduced from X-ray analysis. The reaction of N,N-disubstituted enaminone 5a with tosyl isocyanate gave the product mixture of electrophilic attack on either the α-CH- or the oxygen atom of COCF3 group—vinylog of sulfonylurea 6a and tosylamide 7a , correspondingly.

The interaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one with triethyl phosphite

Abstract 4-Ethoxy-1,1,1-trifluoro-3-buten-2-one reacts with triethyl phosphite on heating to give a [4 + 2 cycloaddition product 2,2,2-triethoxy 2,3-dihydro-3-ethoxy-5-trifluoromethyl-1,2λ 5 -oxaphospholene. Its hydrolysis yields, ultimately, a 2-oxo-2-hydroxy-2, 3-dihydro-3-hydroxy 5-trifluoromethyl-1,2λ 5 -oxaphospholen.

Solvent effects on the infrared spectra of β-alkoxyvinyl methyl ketones: I. Carbonyl and vinyl stretching vibrations

Infrared spectroscopy studies of six beta-alkoxyvinyl methyl ketones, with common structure R(1)O-CR(2)CH-COR(3), where R(1)=R(3)=CH(3), R(2)=H (1); R(1)=C(2)H(5), R(2)=H (2); R(3)=CF(3); R(1)=R(2)=CH(3), R(3)=CF(3) (3); R(1)=C(2)H(5), R(2)=C(6)H(5), R(3)=CF(3) (4); R(1)=C(2)H(5), R(2)=4-O(2)NC(6)H(4), R(3)=CF(3) (5); R(1)=C(2)H(5), R(2)=C(CH(3))(3), R(3)=CF(3) (6) in 11 pure organic solvents of different polarity were undertaken to investigate the solute-solvent interactions and to correlate solvent properties by means of linear solvation energy relationships (LSER) with the carbonyl and vinyl stretching vibrations of existing stereoisomeric forms. It was shown that contrary to simple carbonyl-containing compounds where solvent HBD acidity (alpha) has the largest influence on the nu (CO) band shift to lower wavenumbers, the dipolarity/polarizability (pi) term plays the main role in the interactions of conjugated enones with solvent molecules leading to the nu (CO) and nu (CC) bathochromic band shifts. The trifluoroacetyl group possesses a reduced ability to form hydrogen bonds with solvents. For the nu (CC) band of non-fluorinated enone 1 solvent HBD acidity (alpha) and solvent HBA basicity term (beta) play a perceptible role, whereas for 2 these terms are not significant. beta-Substituents in fluorinated enones such as R(2)=H, C(6)H(5), and C(CH(3))(3) assist in the intermolecular hydrogen bond formation of the carbonyl moiety with HBD solvents, while beta-substituents such as CH(3) and 4-NO(2)C(6)H(4) prevent the CO group to form the H-bonds with HBD solvents (the solvent HBD acidity term (alpha) is not significant). The comparison of four conformers of the enone 1 reveals that (EEE) form is the most polarizable conformer; the influences of the solvent dipolarity/polarizability (pi) and solvent HBD acidity (alpha) term on the bathochromic nu (CO) band shift are opposite to one another.