Lithium tetrafluoro

The stereochemistry of the spirocyclobutanones shown in Scheme 190 seems to be determined by the rate of the ring expansion compared with that of bond rotation. Indeed, in several cases high stereoselectivity is observed (Scheme 190, a), which is quite opposite to that found with lithium tetrafluoro-borate (Scheme 190, b). 

Y. Qin, Z. Chen, J. Liu, K. Amine, Electrochem. Solid-State Lett. 2010, 13, A11-A14. Lithium tetrafluoro oxalato phosphate as electrolyte additive for lithium-ion cells. 

In 2000, Central Glass Co, Ltd. discovered lithium salts containing a structure of oxalic acid, such as lithium tetrafluoro(oxalato)phosphate (175) and lithium difluorobis(oxalato)phosphate (176) [159],... 

Miscellaneous.—OrElimination. Lithium diphenylsulphonium cyclopropylide continues to be used in cyclobutanone synthesis, and a more efficient rearrangement of the initially produced spiro-epoxide is achieved by the use of lithium tetrafluoro-borate. A promising alternative route to cyclobutanones is shown in Scheme 64,... 

An analogue of LiDFOB is lithium tetrafluoro(oxalato)phosphate (LiPF4C204, or LiFOP), in which phosphorous is the coordination center. This salt was initially synthesized by Prof. Brett Lucht s group at the University of Rhode Island. It has... 

Although having P-F bonds in the strucmre, lithium tetrafluoro(oxalato)phos-phate (LiFOP, Fig. 14) has much better thermal stability than LiPFs. Another thermally stable phosphorous-based salt is a tri-chelated salt, lithium tris [l,2-benzenediolato(2)-0,0 ]phosphate (LTBP, Fig. 16) [43], but it cannot be used in the Li-ion battery because of its insufficient electrochemical window related to the less stable phenol ligands. 

The same compound has been obtained by a number of other research groups, using a number of different methods of generating tetrafluoro-benzyne. These include the loss of magnesium halide from pentafluorophenylmagnesium halides 44 46>, the loss of lithium fluoride from penta-fluorophenyl-lithium 47>48), and the aprotic diazotisation of tetrafluoro-anthranilic acid 49>. 

Nucleophilic substitution of dibenzofurans has been little studied. Bromo and iodo compounds are converted into the amino compounds on autoclaving with aqueous ammonia in the presence of copper(I) bromide (730PP125). Iodo compounds can be converted into phenols with aqueous potassium hydroxide at 250 °C (65MI31100), but dibenzofuran is cleaved to 2,2 -dihydroxybiphenyl on fusion with sodium hydroxide. Animation of halo compounds can be achieved with sodamide but 4-halo compounds undergo cine substitution on treatment with sodamide or lithium dialkylamides and the 2-substituted compounds result (56JOC457). 1,2,3,4-Tetrafluoro- and octafluoro-dibenzofuran react with nucleophiles at the 3-position (Scheme 101) (67T4041,68JCS(C)1560). 

Decafluorodibenzoyl reacts with pentafluorophenyl lithium to give 4,5,6,7-tetrafluoro-2,2-bis(pentafluorophenyl)benzofuran-3(2//)-one (9).138... 

Solvents were dried over sodium (light petroleum, bp 40-60°C, toluene) or sodium-benzophenone (diethyl ether, THF). Sodium amide, hexamethyl-disilazane, lithium triethylhydroborate(l —), and hydrogen tetrafluoro-borate(l —) diethyl ether complex were obtained from Aldrich and used as supplied. 

N-Methyl-2-pyrrolidone Ferric chloride hexahydrate Glycol monomethyl ether Lithium aluminum hydride Ruthenium on charcoal Magnesium ethoxide 4-Toluenesulfonic acid Sodium bicarbonate 1,2,3,4-Tetrafluoro benzene Palladium on charcoal Cyclopropylamine N-benzylimide... 

In addition to these cycloaddition reactions with nucleophilic Tr-donors, tetrafluoro-benzyne is very susceptible to more general nucleophilic attack. Biphenyl derivatives often occur as by-products in reactions of pentafluorophenyl-lithium, formed by addition to the benzyne [204, 229] (Figure 9.89). 

BFaN, Borate(III), tetrafluoro-, tetrafluoro-ammonium (1 1), 24 42 BFi303Te3, Tellurate(VI), pentafluorooxo-, boron(3 + ) (3 1), 24 35 BKCsHie, Borate(l-), (cyclooctane-1,5-diyl)dihydio-, potassium, 22 BLiCaHu, Borate(l-), (cyclooctane-1,5-diyl)dihydro-, lithium, 22 199 BNCaHia, Borane, (dimethylamino)diethyl-, 22 209... 

As to acceleration of the isomerization, addition of salts such as lithium perchlorate in acetonitrile solution and tetrabutylammonium tetrafluoro-borate in dichloromethane in DCA-sensitized irradiation of cis-stilbene enhanced the isomerization. A salt effect is probably responsible for retardation of recombination between the resulting stilbene radical cations and counteranions (DCA--, etc.) [143, 146]. 

X.-Y. Li, Z.-M. Xue, J.-F. Zhao, C.-H. Chen, J. Power Sources 2013, 235, 274-279. A new lithium salt with tetrafluoro-l,2-benzenediolato and oxalato complexes of boron for lithium battery electrolytes. 

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