- PROCESS FOR THE PREPARATION OF FLUOROACRYLIC ACID ESTERS
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The present invention provides a process for the preparation of a compound of Formula VI.
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Page/Page column 8; 10
(2017/02/24)
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- A simple and highly diasteroselective approach for the vicinal dichlorination of functional olefins
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Organocatalytic stereospecific vicinal dicholorination of a wide variety of functionalized olefins such as ketoesters, esters, ketones, carvone, cholesterol and ethyl sorbate (27 examples) was achieved using inexpensive sulfuryl chloride as well as a simple phosphine catalyst under mild reaction conditions. The products were obtained with good to excellent yields and diastereoselectivities (up to 96% yield and >25 : 1 dr).
- Zeng, Xianghua,Gong, Chunhua,Zhang, Junyong,Xie, Jingli
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p. 85182 - 85185
(2016/11/11)
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- Chlorination of α,β-Unsaturated Ketones and Esters in the Presence of Acid Scavengers
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The chlorination of a series of α,β-unsaturated ketones and esters by Cl2 in CH3OH, with and without acid scavengers such as N-chlorosuccinimide (NCS), pyridine and 2,6-lutidine, is described.Methyl vinyl ketone and cyclohex-2-enone have also been chlorinated in ethanol.Mixtures of Markovnikov(M) and anti-Markovnikov(AM) methoxy chlorides and dichlorides are formed in most cases; phenyl vinyl ketone gives no M products in the absence of pyridine, M methoxy chloride is not formed with (E)-4-chlorobut-3-en-2-one under any conditions, pyridine has no effect on the product ratios and methyl 3-chlorobut-2-enoate forms only dichloride.Chlorination of the ketones in the presence of the pyridines results in a significant increase in the M regioisomer (except for methyl isopropenyl ketone and the ketones mentioned), giving M : AM ratios which are similar to the corresponding esters.Ratios for the esters are not affected significantly by pyridine.We ascribe the effect of the pyridine bases to the elimination of acid and the acid-catalysed mechanism, permitting the chlorination to occur via a carbon-carbon ?-bond (chloronium ion) mechanism.The rate of chlorination of methyl vinyl ketone is retarded by pyridine but is still considerably faster than methyl acrylate.NCS, in contrast to N-bromosuccinimide (NBS) reported previously, has no effect on the M : AM ratio.The chlorination of methyl vinyl ketone with NCS and HCl gives markedly different results from Cl2.
- Heasley, Victor L.,Elliott, Stephen L.,Erdman, Paul E.,Figueroa, Daphne E.,Krosley, Kevin W.,et al.
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p. 393 - 399
(2007/10/02)
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- Conformational stability, barriers to internal rotation, vibrational assignment, and ab initio calculations of 2-chloropropenoyl fluoride
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The far-infrared spectrum of gaseous 2-chloropropenoyl fluoride, CH2CClCFO, has been recorded at a resolution of 0.10 cm-1 in the region of 350-35 cm-1.The fundamental asymmetric torsional frequencies of the more stable s-trans (two double bonds oriented trans to one another) and the high energy s-cis conformations have been observed at 67.80 and 49.96 cm-1, respectively, each with several excited states falling to lower frequencies.From these data the asymmetric torsional potential function governing the internal rotation about the C-C bond has been determined.The potential coefficients are V1 = - 125 +/- 1, V2 = 1586 +/- 6, V3 = 375 +/- 2, V4 = - 36 +/- 2, and V5 = 65 +/- 1 cm-1.The s-trans to s-cis and s-cis to s-trans barriers have been determined to be 1755 and 1570 cm-1, respectively, with an energy difference between the conformations of 185 +/- 9 cm-1 (529 +/- 26 cal/mol).From studies of the Raman spectrum at variable temperatures, the conformational enthalpy difference has been determined to be 176 +/- 40 cm-1 (503 +/- 114 cal/mol) and 625 +/- 51 cm-1 (1787 +/- 146 cal/mol) for the gas and liquid, respectively.A complete assignment of the vibrational fundamentals observed from the infrared spectra (3500-50 cm-1) of the gas and solid and the Raman spectra (3200-10 cm-1) of all three physical states is proposed.All of these data are compared to the corresponding quantities obtained from ab initio Hartree-Fock gradient calculations employing both the 3-21G* and 6-31G* basis sets.Additionally, complete equilibrium geometries have been determined for both rotamers.The results are discussed and compared with the corresponding quantities obtained for some similr molecules.
- Durig, J. R.,Wang, A. Y.,Little, T. S.,Brletic, P. A.
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p. 905 - 917
(2007/10/02)
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