Lithium fluoroacetates

For simple salts, the influence of different effects can be separately studied by the investigation of series of salts with common anions or cations in a high dielectric permittivity solvent However, high solvent permittivity is just a necessary but not a sufficient condition for complete dissociation. High permittivity of the solvents does not prevent ions from associating if these ions interact specifically and the solvent possesses a poor basicity (DN). Lithium fluoroacetates in PC [202] show association constants of about lO dm moH, which are in the order of many lithium salts with large anions in DME. 

Table 7. Products of the Directed Aldol Reaction of Lithium Enolate of Ethyl Fluoroacetate [/S, 19 ...

One of the syntheses of f1 udalanine begins with base promoted condensation of ethyl fluoroacetate and ethyl oxalate to give This is then converted by hydrolytic processes to the insoluble hydrated lithium salt of fluoropyruvate (58). This last is reductively aminated by reduction with sodium boro-deuteride and the resulting racemate is resolved to give D-flu-dalanine (59). 

The enolates of fluoroacetate or fluorothioacetate esters are generated either through deprotonation with a lithium amide or by an in situ reduction of ethyl bromofluoroacetate with zinc. These enolates can undergo diverse reactions with electrophiles (Figure 2.7) ... 

Under photo-stimulation, isoindolyloxyl radical (5) abstracts primary, secondary, or tertiary hydrogens from unactivated hydrocarbons including cyclohexane, isobutane, or n-butane (Scheme l).23 The nitroxide (5) traps the resultant carbon-centred radical (R ) and so afford the A -aI koxyisoindo les (6). Blank photolysis experiments with no added hydrocarbon have shown some unprecedented / -fragmentation of (5) to afford the nitrone (7). A number of C60 nitroxide derivatives have been synthesized and characterized by ESR spectroscopy which show features common to nitroxide radicals.24 Reaction of nitroxide and thionitroxide radicals with thiyl radicals have been observed, from which sulfinyl, sulfonyl, and sulfonyloxy radicals were generated.25 The diisopropyl nitroxide radical was generated in the reaction of lithium diisopropylamide with a-fluoroacetate esters.26... 

While solvolysis of 5-(4-bromophenylsulfonyloxy)cycloheptene in either acetic acid or tri-fluoroacetic acid after lithium aluminum hydride reduction gave cyclohept-4-enol (71%), cy-clohept-3-enol (12%) and cyclohepta-1,3- and -1,4-diene (5 and 12%, respectively), in contrast acetolysis of 4-(4-bromophenylsulfonyloxy)cycloheptene gave, after saponification with sodium hydroxide in methanol/water, a 78 22 mixture of endo- and exo-bicyclo[4.1.0]heptan-2-ol (1) in 74% yield. Solvolysis of 3-bromocycloheptene afforded, after lithium aluminum hydride reduction, cyclohept-2-enol (37%) and cyclohepta-1,3-diene (63%). ... 

In a related reaction, treatment of the lithinm salt of diethyl (l-phenylsulfonyl)ethylphosphonate with triflnoroacetic anhydride affords triflnoroacetylated phosphonate, which, without isolation, reacts with Grignard reagents in THF at reflux to give trifluoromethylated vinylsulfones in 42-55% yields, with the formation of ( )-isomer exclusively or predominantly. Treatment of the lithium salt of diethyl 1-fluoro-l-(ethoxycarbonyl)methylphosphonate with trimethylsilyl trifluoroacetate leads to the enolate of ethyl (trifluoroacetyl)fluoroacetate, which can further undergo protonation, alkylation, or allylation. °5... 

Two different types of (PS-b-PBDh) diblock can be presently synthesized. The first one by classical anionic initiation (s-buty1-lithium) and "living" propagation of the (PS-b-PBD) copolymer (8), followed by the hydrogenation procedure described here as discussed above, the resulting product will be close to a (PS-b-LLDPE) copolymer. The second one came from the discovery (9) of a "living" polymerization of butadiene into a pure (99 %) 1,4 polymer by a bis n allylnickel-tri-fluoroacetate) coordination catalyst, followed by styrene polymerization unfortunately, the length of the polystyrene block is limited (to a M.W. of ca. 20,000) by transfer reactions. 

Lithium triethylborohydride. CARBONYL COMPOUNDS Catechol-borane. Triethylsilane-Boron triflaoride. EPOXIDES Iron carbonyl. Methyltri-phenoxyphosphonium iodide. Sodium 0,0-diethyl phosphoiotelluioate. Tti-fluoroacetic anhydride-Sodium iodide. 

Metal, Metalloidal, and Non-metal Fluoroacetates.— Fluorine Magnetic Resonance Studies.I.para-Substituted P-DifluorostyTeae [thepP-difluorostyrenesp-XC,H(-CH CFs (X — NMe OMe, Me, H, F, Cl, or CN) were obtained via the CF,Cl-CO,Na-Ph,P-aldehyde route]. Reaction of Difluorocarbene with 2-Benzylidenecyclohexanones to afford Phenylfluorofurans (CF2 generated via thermal decomposition of CF CI-COjNa). Cyclodecapentaene Derivatives (reaction of CF, from CFjCI-COjNa with 1,4,5,8-tetrahydronaphthalenes). Action of Sodimn and Lithium Chlorodifluoroacetates on... 

C2H2DLi03, Lithium a-monodeuterioglycolate, 3IB, 25 C2H2FNa02, Sodium fluoroacetate, 43B, 20... 

---