Coupling reactions copper acetate

In similar work, CF3CCI2CO2CH3 yields methyl a-trifluoromethyl-a,(i-un-saturated carboxylates when reacted with a zinc-copper couple, aldehydes, and acetic anhydride [67] (equation 55). This methodology gives (Z)-a-fluoro-a- -un-saturated carboxylates from the reaction of carbonyl compounds with CFCI2CO2CH3 and zinc and acetic anhydride [6 ]. 

Several techniques have been used to activate the zinc metal and improve yields. For example, pretreatment of zinc dust with a solution of copper acetate gives a more reactive zinc-copper couple.168 Exposure to trimethylsilyl chloride also activates the zinc.169 Wilkinson s catalyst, RhCl(PPh3)3 catalyzes formation of Reformatsky reagents from diethylzinc, and reaction occurs under very mild conditions.170... 

Tributylstannyl)-3-cyclobutene-1,2-diones and 4-methyl-3-(tributylstan-nyl)-3-cyclobutene-l,2-dione 2-ethylene acetals undergo the palladium/copper-catalyzed cross coupling with acyl halides, and palladium-catalyzed carbon-ylative cross coupling with aryl/heteroaryl iodides [45]. The coupling reaction of alkenyl (phenyl )iodonium triflates is also performed by a palladium/copper catalyst [46],... 

Copper acetate-benzidine acetate test (DANGER THE REAGENT IS CARCINOGENIC.) This reaction takes place because the oxidation-reduction potential of the copper(II)-copper(I) couple is increased if copper(I) ions are removed by cyanide ions. 

The oxidation-labile TL 1.44 (102) was readily prepared from aminomethyl PS resin and used to decorate the aryl moiety with C-C coupling reactions (e.g. Heck, Stille, Suzuki, and Sonogashira protocols). Oxidation of the hydrazide moiety to acyl diazene [copper acetate or A -bromosuccinimide (NBS)] and nucleophilic cleavage (methanol or n-propylamine) produced the desired aryl products. 

Lam and coworkers reported that hypervalent arylsiloxanes also react with a variety of substrates containing N—H bonds, in this case in the presence of stoichiometric amounts of copper acetate at room temperature in air without added base (equation 75)303. The hypervalent arylsiloxanes are generated by the addition of tctra-//-butylammonium fluoride (TBAF) to phenyltrimethoxysilane. The rate of these reactions was an order of magnitude faster than the rate of the corresponding reactions with boronic acids. Aromatic amides with heteroatoms in the a-position also coupled with hypervalent arylsiloxanes304. As a function of the a-heteroatom, the rates followed the trend N > S > O. These data are consistent with chelation of the a-substituents. 

A solution of /7-chloroaniline in water (100 ml) and hydrochloric acid (80 ml) is diazotized at 0° by a solution of sodium nitrite (15 g) in water (30 ml). The clear (filtered, if necessary) diazonium solution is added to a cold solution of cinnamic acid (30 g) in acetone (250 ml). Then sodium acetate (44 g), followed by a solution of copper(n) chloride (8.5 g) in water (20 ml), are added. The temperature may rise slowly to 16° when gas evolution has begun. The mixture is stirred at 14-16° for 3 h. By the end of the coupling reaction two layers will have been formed — an upper layer of dark green oil and a lower layer of pale green aqueous acetone. The whole is distilled in steam. The residue is extracted in benzene and washed several times with 3N-ammonia solution and then with water. Distilling off the benzene leaves a crystalline residue of 4-chloro-stilbene which recrystallizes from 2-propanol in shiny leaflets, m.p. 129° (40%). 

Joint catalysis by tin(IV) chloride and zinc chloride induces coupling of the acetal 114 with the alkyne 115 to give the propargyl ether 116. Allyl halides condense with terminal alkynes in DMF in the presence of copper(I) iodide, potassium carbonate and tetrabutylammonium chloride under phase-transfer conditions to afford eneynes, e.g. equation 19. Palladium-catalysed coupling reactions of 1-bromoallenes with terminal acetylenes have been reported for the first time thus acetylene and the allenes 117 (R R = Me or Et) in triethylamine in the presence of tetrakis(triphenylphosphine)palladium and... 

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