Cesium acetate

Potassium acetate, mbidium acetate, and cesium acetate are very soluble ia anhydride ia contrast to the only slightly soluble sodium salt. Barium forms the only soluble alkaline earth acetate. Heavy metal acetates are poorly soluble. 

Other Cesium Compounds. Cesium acetate [3396-11-0], CsOOCCH, mol wt 191.95, theoretical cesium content 69.24 wt % cesium trifluoroacetate, CF COOCs, mol wt 245.93, theoretical cesium content 54.04 wt % cesium—precious metal compounds such as cesium dicarbonyltetrachloromthenium, [22594-81-6] Cs2RuCl4(CO)2, mol wt 564.71, mthenium content of 17.9 wt %, a yellow crystalline powder and cesium tetrachlorogold [13682-60-5], CsAuCl, mol wt 471.7, gold content of 41.8 wt % a yellow powder are all known. 

The Perkin reaction is of importance for the iadustrial production of coumarin and a number of modifications have been studied to improve it, such as addition of a trace of iodine (46) addition of oxides or salts of metals such as iron, nickel, manganese, or cobalt (47) addition of catalytic amounts of pyridine (48) or piperidine (49) replacement of sodium acetate by potassium carbonate (50,51) or by cesium acetate (52) and use of alkaU metal biacetate... 

In the last decade, the mesoporous molecular sieve MCM-41 has been developed (2S2) and applied as a catalyst to many acid-catalyzed reactions (2SS). However, until now, comparatively few investigations of mesoporous molecular sieves as base catalysts have been reported (169,211-214,234,235). For example, sodium- and cesium-exchanged mesoporous MCM-41 were shown to be mildly selective, water-stable, recyclable catalysts for the base-catalyzed Knoevenagel condensation, and mesoporous MCM-41 containing intraporous cesium oxide particles prepared by impregnation with aqueous cesium acetate and subsequent calcination was found to have strong-base activity for the Michael addition (211,213) and rearrangement of co-phenylalkanals to phenyl alkyl ketones (212). 

The synthesis of phosphino sulfoximine 97 relied significantly on the successful development of methods pursued in parallel in our group. Whereas palladium-catalyzed cross-couplings between 53 and 98 proceeded in low yield, the copper catalysis with a combination of copper(l) iodide and cesium acetate worked well, affording 99 in up to 83% yield [78]. The resulting phosphine oxides 99 were then reduced to the corresponding phosphines 97 using a mixture of trichlorosilane and triethylamine (Scheme 2.1.1.33). 

Iodopyridine is converted into 2-butylaminopyridine in 80% yield on treatment with -butylamine and 0.5 equivalents of relatively inexpensive copper(I) iodide with cesium acetate in DMF <2003OL4987>. Using copper(I) iodide as catalyst, in ethylene glycol with potassium phosphate as base, in air, 3-bromopyridine couples with /z-hexylamine in 85% yield at 80C <20020L581>. 

Alcohol inversion. Elimination competes with S, 2 substitution in the inversion of secondary alcohols by the Mitsunobu reaction or by reaction of mesylates with cesium propionate or cesium acetate. Elimination in the inversion of cyclopentyl and cyclohexyl alcohols can be largely suppressed by reaction of the mesylate with cesium acetate (excess) and a catalytic amount of l8-crown-6 in refluxing benzene. Even inversion of an ally lie alcohol can be effected in moderate yield under these conditions (equation I). ... 

Cesium uranyl triacetate was precipitated by adding a solution of cesium acetate containing a small amount of acetic acid to a solution of uranyl acetate in water. This previously reported compound was not analyzed. 

Koepp, E., Voegtie, F. Perkin syntheses with cesium acetate. Synthesis 1987, 177-179. 

Recently, it has been reported that significantly higher yields are obtained and shorter reaction times required in the Perkin synthesis of cinnamic acids when sodium acetate is replaced by cesium acetate. ... 

The same authors reported [83] that strongly basic sites are created when MCM-41 is impregnated with cesium acetate and then subjected to thermal treatment to produce highly dispersed CS2O particles. This material was tested in the Michael addition of neopentyl glycol diacrylate (8) with diethyl malonate (9). The reactant 8, with two isolated activated double bonds, can afford a mono adduct (10) and/or a bis adduct (11) (Scheme 7). Table 3 shows the performance of the catalyst as a function of Cs atom loading and Si/Al ratio. 

A novel 2-arylation of A -substituted indoles has been reported <04OL2897>. Treatment of indole substrates with palladium acetate, triphenylphosphine, cesium acetate and aryl iodides led to the formation of 2-arylindoles. 

It has been reported that microwave irradiation shortens the reaction time of the Perkin reaction by 60-fold over classical heating. Cesium salts (acetate, carbonate, fluoride) with a small amount of pyridine were found to be the best catalysts.12 Thus, p-hydroxybenzaldehyde (45) reacted with acetic anhydride using cesium acetate as a catalyst to provide the a, p-unsaturated acid 46 in 85% yield. 

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