- THE REACTION OF SOME 3- AND 4-FLUOROOXETANES WITH ACIDS
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Several oxetanes prepared from hexafluoroacetone and hydrofluoroolefins were treated with aluminum chloride.Substitution of fluorine by chlorine occured on the 3- and 4-carbon atoms as well as cleavage of the ether leakage to give chloroalkyl carbinols or in, some cases, vinyl carbinols.Individual samples of the cis and trans-3,4-difluorooxetanes formed roughly equivalent amounts of the 3-fluoro-4-chlorooxetane stereoisomers, indicating a common carbonium intermediate.Treatment of the 4-fluorooxetane with sulfuric acid gave a dioxetane, a dioxene and an unsaturated aldehyde.
- Tarrant, Paul,Bull, R. N.
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- Synthesis of Bis(trifluoromethyl)-Substituted Olefins: Methods of Preparation and Properties
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Several bis(trifluoromethyl)- and trifluoromethyl-substituted alkenes, dienes, arylalkenes, and α,β-unsaturated derivatives of carbonyl compounds such as tosylhydrazone 5b and diazomethane 5c were prepared.Their reactivity towards a variety of nucleophiles, resulting from the electron-withdrawing effect of the trifluoromethyl group, was investigated.Depending on the trifluoromethyl- and a bis(trifluoromethyl)-substituted double bond, different regioselectivities were observed in the reaction with morpholinocyclohexene as a nucleophile.An explanation is given on the basis of the 13C-NMR data. - Keywords: Trifluoromethyl-substituted alkenes; anti-Michael addition; Acceptor-substituted double bond; Steric demand of a CF3 group; Charge-shift correlation
- Haas, Alois,Lieb, Max,Zwingenberger, Joerg
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p. 2027 - 2036
(2007/10/03)
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- Efforts in Synthesizing α,β-Unsaturated Trifluoromethyl-substituted Aldehydes
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Hexafluoroacetone reacts with ethynylmagnesium bromide to yield (CF3)2C(OH)-CCH (1).Bromine can be added to the triple bond affording the cis/trans-isomer 2.With PCl5 1 yields the allene (CF3)2C=C=CClH (3).The addition of a metalated Schiff base to hexafluoroacetone leads to 4a which on hydrolysis yields (CF3)2C(OH)-CH2-CHO (4b).The reaction of (EtO)2P(O)CH2-R (R = CHO, CO2Et) with hexafluoroacetone gives α,β-unsaturated aldehydes or esters 6. 1,1,1-Trifluoroacetone provides analogous reactions.
- Abele, Herbert,Haas, Alois,Lieb, Max
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p. 3502 - 3506
(2007/10/02)
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