Search results for "Tetralone"
showing 10 items of 10 documents
E-2-Benzylidenebenzocycloalkanones. IV. Studies on transmission of substituent effects on 13C NMR chemical shifts of E-2-(X-benzylidene)-1-tetralones…
2005
Abstract Single substituent parameter (SSP) and dual substituent parameter (DSP) analyses were applied to study the transmission of substituent effects on selected 13C NMR chemical shifts of the cyclic chalcone analogues, E-2-(4′-X-benzylidene)-1-tetralones (2) and E-2-(4′-X-benzylidene)-1-benzosuberones (3). In order to study how the geometry of the cyclic chalcone analogues affects the transmission of substituent effects similar investigations with the respective chalcones (4) were also performed. The results obtained earlier with the five-membered analogue E-2-(4′-X-benzylidene)-1-indanones (1) were also involved in the comparisons. Geometry optimization of the unsubstituted 1a, 2a, 3a a…
First synthesis of the chiral mixed O/S ligands, 1,2-sulfinyl thiols: application as chiral proton sources in enantioselective protonations of enolat…
2000
Abstract A suitable method for the preparation of the chiral mixed O/S ligands 1,2-sulfinyl thiols is described. These compounds have then been used as a chiral proton source in the enantioselective protonation of 2-methyl tetralone enolate and the results are compared with those obtained from the analogous alcohols. A theoretical model is proposed to explain the different behaviors exhibited in the protonation reaction for each of these proton sources. Configurational assignments for the new chiral thiols have been carried out by means of X-ray analysis.
E-2-Benzylidenebenzocycloalkanones III. Studies on transmission of substituent effects on IR carbonyl stretching frequencies and 13C NMR chemical shi…
2004
Abstract Single substituent parameter and dual substituent parameter analysis was applied to study transmission of substituent effects on IR carbonyl stretching frequencies of E -2-(X-benzylidene)-1-indanones ( 3 ), -tetralones ( 4 ), and -benzosuberones ( 5 ). Similar analyses were performed for selected 13 C NMR chemical shifts of some E -2-(X-benzylidene)-1-indanones ( 3 ). For a better understanding of the results semiempirical and ab initio quantum chemical calculations were performed to determine the preferred geometry and to calculate the theoretical 13 C NMR chemical shifts of the selected compounds ( 3 ). The differences among the regression coefficients were discussed in terms of …
Cu/P(4-PVP) stereochemistry in tetralin liquid-phase oxidation
2007
Abstract Cu/P(4-PVP) catalyst was used as catalyst for oxidation of tetralin in liquid phase. The catalyst was prepared by reaction of a Cu(II) salt with a 4-vinylpyridine-co-divinylbenzene polymer receptor and characterized by solid 1 H and 13 C NMR, XPS, FTIR, ESR spectroscopies, and by chemical reaction with pure tetralin. That information was used to gain insight into the stereochemistry of the active site needed to orient the reaction toward tetralone production. It was found that the Cu coordination with the pyridine was critical in influencing the peroxy-radical catalytic reaction, and that polyvinylpyridine was able to limit the autothermal oxidation. The active center is postulated…
Total Synthesis of (-)-C/D-cis-Dehydro-3-O-methyl-estradiols
2015
A convergent synthesis of (–)-dehydro-3-O-methyl-C/D-cis-estradiol started from stereochemically defined substituted optically active 3-(2-arylethyl)-γ-butyrolactones. Regioselective bromination of the anisyl moiety, reductive ring opening of the iodolactone, and protecting-group changes led to a Weinreb amide. This then underwent an intramolecular Grignard reaction closing the B-ring to give a tetralone with defined configuration. Introduction of C-11 through an allyl Grignard addition and subsequent ring-closing metathesis gave a tetrahydro phenanthrene derivative. Oxidation of the side-chain alcohol resulted in the key aldehyde group, and a final samarium-diiodide-mediated reductive D-ri…
An improved method for the asymmetric protonation of enolates with chiral α-sulfinyl alcohols/trifluoroethanol
2001
Abstract Enantioselective protonation of 2-methyl tetralone enolate using a stoichiometric amount of 2-sulfinyl alcohol ( S , R s )- 1 as a chiral proton donor yields the corresponding chiral ketone with a high level of enantioselectivity, provided that the chiral proton donor (CPD) is regenerated with an achiral proton source (APS). In contrast, stereoselectivity was only moderate if catalytic CPD (0.2 equiv.) and an APS are used.
ChemInform Abstract: Remarkable Effect of Lithium Bromide in the Enantioselective Protonation with α-Sulfinyl Alcohols.
2010
Abstract The favourable effect of lithium bromide enhancing the facial enantioselectivity in the protonation of methyl tetralone enolate with α-sulfinyl alcohols is described. Theoretical calculations allow to propose a model to explain the stereochemical course of the protonation reaction.
Remarkable effect of lithium bromide in the enantioselective protonation with α-sulfinyl alcohols
1998
Abstract The favourable effect of lithium bromide enhancing the facial enantioselectivity in the protonation of methyl tetralone enolate with α-sulfinyl alcohols is described. Theoretical calculations allow to propose a model to explain the stereochemical course of the protonation reaction.
ChemInform Abstract: First Synthesis of the Chiral Mixed O/S Ligands, 1,2-Sulfinyl Thiols: Application as Chiral Proton Sources in Enantioselective P…
2001
Abstract A suitable method for the preparation of the chiral mixed O/S ligands 1,2-sulfinyl thiols is described. These compounds have then been used as a chiral proton source in the enantioselective protonation of 2-methyl tetralone enolate and the results are compared with those obtained from the analogous alcohols. A theoretical model is proposed to explain the different behaviors exhibited in the protonation reaction for each of these proton sources. Configurational assignments for the new chiral thiols have been carried out by means of X-ray analysis.
Crystal structure of 4-(4-meth-oxy-phen-yl)-4',4'-dimethyl-3-p-tolyl-3',4'-di-hydro-1'H,3H-spiro-[isoxazole-5,2'-naphthalen]-1'-one.
2015
In the title compound, C28H27NO3, the cyclohexanone and isoxazole rings have envelope conformations, with the methylene and spiro C atoms as the flaps, respectively. The mean plane of the isoxazole ring is inclined slightly to thep-tolyl ring, making a dihedral angle of 14.20 (9)°, and is nearly perpendicular to the mean plane through the tetralone moiety and to the methoxyphenyl ring [dihedral angles = 83.41 (8) and 72.12 (9)°, respectively]. The crystal packing is stabilized mainly by van der Waals forces.