Aryl triflates carbonylation

The most useful pseudo-halides are aryl triflates (trifluoromethylsulfonates) of phenols and enol triflates derived from carbonyl compounds[4,5,6]. 

Carboxylic acids are produced in water. Selection of solvents is crucial and the carbonylation of the enol triflate 480 can be carried out in aqueous DMF, and that of the aryl triflate 481 in aqueous DMSO using dppf as a ligand[328,334]. The carbonylation of the enol triflate 482 to form the a, 0. unsaturated acid 483 using dppf as a ligand in aqueous DMF has been applied in the total synthesis of multifunctionalized glycinueclepin[335]. 

The aryl- and heteroarylfluorosilanes 541 can be used for the preparation of the unsymmetrical ketones 542[400], Carbonylation of aryl triflate with the siloxycyclopropane 543 affords the 7-keto ester 545. In this reaction, transme-tallation of the siloxycyclopropane 543 with acylpalladium and ring opening generate Pd homoenolate as an intermediate 544 without undergoing elimination of/3-hydrogen[401],... 

On the other hand, the use of [Rh(CO)2Cl]2 as a catalyst results in ring opening of the siloxycyclopropanes 13 to the silyl enol ethers 14 with high stereoselectivity [10]. The 2-siloxyrhodacyclobutane 15a is proposed to undergo j8-elimination to give jr-allylrhodium 16a followed by reductive elimination to the silyl enol ether 14a. 1-Trimethylsiloxybicyclo[n.l.0]alkanes serve as / -metallo-carbonyl compounds via desilylation with a variety of transition metals [11]. The palladium-catalyzed reaction of the siloxycyclopropanes 17 under carbon monoxide in chloroform provides a route to the 4-keto pimelates 18. In the presence of aryl triflates, the 1,4-dicarbonyl compounds 19 are... 

Carbonylative cross-coupling of iodoarenes and aryl triflates with g< ///-fluorovinyltributylstannane takes place smoothly in a standard system, with triflate substrates requiring the addition of tetrabutylammonium iodide (Equation (4)). ... 

Carbonylation of enol triflates derived from ketones and aldehydes affords a,/3-unsaturated esters[332]. Steroidal esters are produced via their aryl and enol triflates[328]. The enol triflate in 477 is more reactive than the aryl triflate and the carbonylation proceeds stepwise. First, carbonylation of the enol triflate affords the amide 478 and then the ester 479 is obtained in DMSO using dppp[333],... 

Synthesis of arylboronates via the palladium(0)-catalyzed cross-coupling reaction of tetra(alkoxy)diboranes with aryl triflates has been reported.114 The cross-coupling reaction of (RO)2B-B(OR)2 (OR = methoxy and pinacolato) with aryl triflates to give arylboronates 178-189 was carried out at 80 °C in the presence of PdCl2(dppf) (3 mol%), and KOAc (three equivalents) in dioxane. The reaction was generalized to various functional groups such as nitro, cyano, ester, and carbonyl groups (Scheme 30). 

Echavarren, A. M., Stille, J. K. Palladium-catalyzed carbonylative coupling of aryl triflates with organostannanes. J. Am. Chem. Soc. 1988, 110, 1557-1565. 

Palladium-catalyzed carbonylation of aryl triflates in the presence of an alcohol141 or amine1423 provides a good method for preparation of arenecarboxylic esters and amides from phenols (equation 121). However, palladium-catalyzed cyanation of 5,6,7,8-tetrahydro-2-naphthyl triflate with potassium cyanide failed completely whereas the more reactive tetrakis(triphenylphosphine)nickel(0) could catalyze the same reaction which gives the nitrile in a good yield142b (equation 122). 

Reaction of diphenylsulfoxide with triflic anhydride affords, as precedently mentioned, the corresponding sulfoxonium triflate, a powerful reagent for numerous reactions, such as a-arylation of carbonyls, enolate additions,or nucleophilic substitution on alkenes (102). ... 

In palladium-catalyzed carbonylations, aryl triflates are used regularly as substrates [145-151], while arene diazonium salts [152-156] and diaryl iodonium salts [157-162] are less commonly applied. 

In 2007, BeUer and his colleagues developed the first general palladium-catalyzed carbonylation of aryl triflates with synthesis gas [39]. In contrast to aryl bromides, only the bidentate ligands dppe and dppp led to significant conversion... 

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