- PROCESS FOR PREPARATION OF FLUOROFORMATES
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A process for the preparation of fluoroformates of the formula wherein R1 is a saturated or unsaturated, substituted or unsubstituted and primary or secondary aliphatic, a saturated or unsaturated, substituted or unsubstituted secondary cycloal
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- Synthesis of vinyl carbonates for use in producing vinyl carbamates
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A method for making a vinyl carbonate represented by the formula (I): CH2═CHOC(O)X1R1??(I) wherein X1is oxygen or sulfur and R1is a substituted or an unsubstituted aliphatic alkyl, aryl, aryl alkyl, olefinic, vinyl, or cycloaliphatic group comprises: (a) reacting a compound represented by the formula (II): X2C(O)X1R1??(II) ?wherein X2is a halogen other than fluorine, with a compound represented by the formula (III): M1—F??(III) ?wherein M1is selected from a Group IA metal, in the presence of a first phase transfer catalyst and a first organic solvent, to form a compound represented by the formula (IV): FC(O)X1R1??(IV) and (b) reacting a compound represented by the formula (IV) with a compound represented by the formula (V): CH2═CHOSi(R2)3??(V) ?wherein R2is a substituted or an unsubstituted aliphatic alkyl, aryl, aryl alkyl olefinic, vinyl, or cycloaliphatic group, or any combination thereof, in the presence of a metal salt represented by the formula M2—F wherein M2is a Group IA metal, a second phase transfer catalyst, and a second organic solvent, to form the compound represented by formula (I).
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- Synthesis of vinyl carbonates for use in producing vinyl carbamates
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A method for making a vinyl carbonate represented by the formula (I): CH2═CHOC(O)X1R1??(I) wherein X1is oxygen or sulfur and R1is a substituted or an unsubstituted aliphatic alkyl, aryl, aryl alkyl, olefinic, vinyl, or cycloaliphatic group comprises: (a) reacting a compound represented by the formula (II): X2C(O)X1R1??(II) wherein X2is a halogen other than fluorine, with a compound represented by the formula (III): M1—F??(III) wherein M1is selected from a Group IA metal, in the presence of a first phase transfer catalyst and a first organic solvent, to form a compound represented by the formula (IV): FC(O)X1R1??(IV); ?and (b) reacting a compound represented by the formula (IV) with a compound represented by the formula (V): CH2═CHOSi(R2)3??(V) wherein R2is a substituted or an unsubstituted aliphatic alkyl, aryl, aryl alkyl olefinic, vinyl, or cycloaliphatic group, or any combination thereof, in the presence of a metal salt represented by the formula M2—F wherein M2is a Group IA metal, a second phase transfer catalyst, and a second organic solvent, to form the compound represented by formula (I).
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- Preparations of carboxylic acid esters containing heptafluoroisopropyl groups
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The reaction of fluoroglyoxylic acid esters and fluoroformic acid esters with perfluoropropene (PFP) yielded perfluoro(3-methyl-2-oxobutyric) acid esters and perfluoroisobutyric acid esters, respectively.Oxamide derivatives and 2,3-quinoxalinediol have been prepared by the reaction of perfluoro(3-methyl-2-oxobutyric) acid esters with amines and o-phenylenediamine, respectively.Perfluoro(3-methyl-2-oxobutyric) acid esters give perfluoroisobutyric acid esters on heating in the presence of fluoride ion in an aprotic solvent.
- Suyama, T.,Kato, S.,Mizutani, Y.
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- A Simple Conversion of 1-Chloroethyl Carbonates to Fluoroformates: Value in the Preparation of Tertiary Alkyl Fluoroformates
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When the economical and easily available 1-chloroalkyl carbonates (RCHClOCO2R') are heated neat or in solution with KF in the pesence of 18-crown-6 catalyst, they fragment to aldehydes (RCHO) and fluoroformates (FCO2R').If the system is evacuated during reaction and either or both products are removed as formed, then the process is driven to completion and fluoroformates are isolated in good yield.The new methodology (which exemplifies an unusual conversion of an ester to an acid halide) is especially valuable in the synthesis of important tertiary alkyl fluoroformates and benzyl fluoroformate (with R as CH3 in the carbonate): tert-butyl fluoroformate (BOC-F, 84percent yield), tert-amyl fluoroformate (83percent), 1-adamantyl fluoroformate (76percent), benzyl fluoroformate (60percent).Boc-F previously has been recommended as a superior reagent for the preparation of Boc-amino acids, but earlier routes to this reagent have been expensive and impractical.When R in the carbonate reactant is Cl3C, the reaction proceeds cleanly without the 18-crown-6 catalyst (Boc-F in 79percent yield).This latter variation is most useful on a small industrial scale.
- Dang, Vu Anh,Olofson, R. A.,Wolf, Patrick R.,Piteau, Marc D.,Senet, Jean-Pierre G.
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p. 1847 - 1851
(2007/10/02)
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- Acylation du trifluoromethoxybenzene en catalyse HF-BF3
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Friedel and Crafts acylation of trifluoromethoxy- and trifluoromethyl-thiobenzene fails to give ketones in a one step synthesis if chlorinated Lewis acids (AlCl3) are used, because of halogen exchange on the -OCF3 and -SCF3 groups.The use of a fluorinated catalyst system such as HF-BF3 avoids exchange reactions and acylation occurs smoothly under mild conditions: - Low temperature and pressure - High yields (very often >90 percent) - Very high para-regioselectivity.Related reactions such as formylation or sulfonylation can also be achieved under similar conditions.
- Desbois, Michel
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p. 885 - 890
(2007/10/02)
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- Process for the preparation of fluoroformates
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A process for the preparation of fluoroformates of formula: STR1 in which R1 is a substituted or unsubstituted, saturated or unsaturated aliphatic, cycloaliphatic or polycyclic radical, or substituted or unsubstituted araliphatic radical or an aromatic radical, which consists of reacting a carbonate of formula: STR2 in which R1 has the same meaning as hereinabove and R2 is hydrogen, alkyl of 1-12 carbon atoms, cycloalkyl of 5-12 carbon atoms, saturated or unsaturated, unsubstituted or substituted by one or more halogen atoms or R2 is aryl, unsubstituted or substituted by one or more halogen atoms, with an alkali or alkaline earth fluoride, ammonium fluoride or a quaternary ammonium fluoride, of formula FNR3 R4 R5 R6, wherein R3, R4, R5, R6 are the same or different and are hydrogen, alkyl or aralkyl of 1-12 carbon atoms or a fluoride which is KHF2, NH4 HF2 or KSO2 F. The fluoride is activated by a complexing agent for the cation which is a cryptate, a cyclic or linear polyether or by means of a polar aprotic compound. The carbonate is split to give a reaction mixture containing an aldehyde and the fluoroformate which is removed from the reaction mixture.
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