Cyclopropenylium salts, reaction with

The reaction of trisubstituted cyclopropenylium salts 1 with hexacarbonylmolybdenum(O) or tetracarbonylmolybdenum(O) complex afforded the complex salt 15 or 16. The same reaction with 17, followed by treatment with thallium cyclopentadienide, yielded complex 18. - The structures of 16 (X = Br) and 18 (R = Ph, t-Bu) were determined by X-ray crystallography. 

Isolation of 3-cyclopropenyl metal compounds by this method has been achieved so far for iron and rhenium metals only. Thus, the reaction of Na[CpFe(CO)J (NaFp) with cyclopropenylium salts at -70 °C, in THF, gave 3-Fp-cyclopropene complexes (equation 194)2 267. The X-ray crystal structure of the most stable iron complex 3-Fp-C3Ph3 exhibits a regular cyclopropene C—C single and double bond distances (151 and 129 pm), and a characteristic distance of 208 pm for the Fe—C (T-bond267. The H NMR (CS2) spectrum of the 3-Fp-C3Ph,H complex displays a singlet at S = 2.63 ppm, of the cyclopropen yl proton at the 3-position. ... 

The major route to -cyclopropenylium complexes L M(C3R3) (metallatetrahedranes) is by oxidative addition reactions of cyclopropenylium salts to transition metal complexes of groups 5 (V), 6 (Mo, W), 8 (Fe, Ru), 9 (Co, Rh, Ir) and 10 (Ni, Pd, Pt). The addition is frequently accompanied by loss of one or more carbonyl, olefin or halogen auxiliary ligand. Concurrent formation of oxocyclobutenyl complexes by carbonyl insertion into the cyclopropenyl ring is often observed in reactions with group 9 cobalt triad and early transition metal complexes. 

T-Bound cyclopropenylium cation complexes of palladium 4 were formed upon reaction of 1,1-dichlorocyclopropenes with palladium metal. Protonolysis resulted in decomplexation to give the free cyclopropenylium salt 5. ... 

Reaction of tris(tert-butylsulfanyl)cyclopropenylium salt with anhydrous sodium hydrogen carbonate in refluxing ethyl acetate gave the thione 5 in 90% yield. This reaction has not been used for the preparation of other cyclopropenethiones. 

In the presence of a mineral acid, the reaction of bis(isopropylamino)cyclopropencthiones with acrylamide or 1,4-benzoquinone afforded [2-(aminocarbonyl)ethylsulfanyl]bis(diisopropyl-amino)cyclopropenylium bromide (using HBr, EtOH) and (2,5-dihydroxyphenylsulfanyl)-bis(diisopropylamino)cyclopropenylium perchlorate (using HCIO4, EtOH), respectively. Reaction of bis(diisopropyl)cyclopropenethionc with chlorobis(diisopropyl)cyclopropenylium salts in chloroform afforded a sulfur bridged dication 3. °" ... 

The reaction of disubstitutcd acetylenes 1 with arylchlorocarbenes, which were generated by the action of strong base upon (dichloromethyl)benzcnes 2, afforded the cyclopropenyl halides 3. The halides, or the cyclopropenyl alkoxides obtained therefrom, were readily converted to the cyclopropenylium salts 4 upon treatment with Bronsted acids. ... 

Tetrachlorocyclopropene (3) was converted into the highly stabilized triaminocyclopropenylium salts 12 by direct reaction with excess amounts of the secondary amines in dichloromethane followed by treatment with perchloric acid. ° In the case of diethylamine, the reaction was so slow that it could be stopped at the disubstitution stage to give the chlorobis(diethylamino)-cyclopropenylium ion 13, which was further treated with more reactive amines to give the mixed triaminocyclopropenylium salts 14. ... 

The tris(methylsulfanyl)cyclopropenylium salt 19 was also prepared from tetrachlorocyclo-propene (3) by the reaction with dirnethyl(methylsulfanyl)sulfonium tetrafluoroborate and dimethyl disulfide." ... 

Tetrabromocyclopropene (21) reacted very readily with dimethyl diselenide and with dimethyl ditelluride to give the tris(methylchalcogeno)cyclopropenylium tribromidcs 22 in high yield. The reaction with dimethyl disulfide was slower but also afforded the tris(methylsulfanyl)cyclo-propenylium salt in high yield. 

The reaction of disubstituted cyclopropenones with nitrogen-containing hcteroaromatic rings, such as indoles. indolizincs. pyrroles, and pyridazincs, " under acidic conditions afforded the corresponding trisubstituted cyclopropenylium salts 16-20 in high yields. 

The reaction of di-/er/-butylcyclopropenone (21) with alkyl- and phenyllithiums, followed by ordinary workup, gave the bis(trisubstituted cycloprop-2-enyl) ethers 22, which were converted to the trisubstituted cyclopropenylium salts 23 upon subsequent treatment with a strong Bronsted acid such as perchloric or hydrobromic acid. ... 

The reaction of diarylcyclopropenones 1 with aryl- or cyclopropylmagnesium °° bromide and hydrolysis using aqueous potassium dihydrogen phosphate solution, followed by treatment with a strong Bronsted acid such as tetrafluoroboric - or hydrobromic acid, afforded the trisubstituted cyclopropenylium salts 26. 

In the presence of hydrobromic acid, 2,3-bis(diisopropylamino)cyclopropenethione (29) was S-alkylated by acrylamide in ethanol.A similar reaction with 1,4-bcnzoquinone and perchloric acid in ethanol resulted in S-arylation to give cyclopropenylium salt 38. ° ... 

The chlorine atom of chlorocyclopropenylium ions can be replaced with other heteroatom substituents. Thus, the l,2-diamino-3-chlorocyclopropenyliumsalts 1 were converted to various derivatives of trisubstituted cyclopropenylium salts by the reaction with amines, silylamines, hydrazine,and triphenylphosphane. ... 

When l,2,3-tris(rf rt-butylsulfanyl)cyclopropenylium tetrafluoroborate (29) was treated with anilines, one of the tert-butyl groups was replaced by the phenylamino group to give the 1-arylamino-2,3-bis(mrr-butylsulfanyl)cyclopropenylium salts 30. The reaction with alkyl-amines of higher basicity, however, caused cleavage of the cyclopropenylium ring, giving rise to vinylazomethine-type iminium salts. 

The tris(tert-butylsulfanyl)cyclopropenylium ion 11 readily reacted with trialkyl phosphites to give the (cycloprop-2-enyl)phosphonate derivatives 12 but not with triphenyl phosphite, even under more forcing conditions. The reaction with hexamethylphosphorous triamide gave the (cycloprop-2-enyl)phosphonium salt 13. Similarly, the tri-tert-butylcyclopropenylium ion 14 reacted with lithium bis(trimethylsilyl)phosphide affording the 3-phosphanylcyclopropene derivative 15 in high yield. 

Analogously, the reaction of rhenate pentacarbonyl anion [Re(CO)5] as its sodium salt, with cyclopropenylium cations [C3Ph3]X (X = BF4, PF6) in THF, at -80 °C, afforded the octahedral n-coordinated pentacarbonyl ( /-l,2,3-triphenylcyclopropenyl)rhenium complex in 60-73% yield (equation 195)26 269. The l3C NMR (acetone-, .) spectrum dis-... 

Gradually in dichloromethane, and almost instantaneously in acetonitrile, l,2-dichloro-3-(dimethylamino)cyclopropenylium hexachloroantimonate (14) underwent a disproportionation reaction to give the corresponding diaminochlorocyclopropenylium salt 15 in 80% yield together with the trichlorocyclopropenylium salt 13/" ... 

The first example of a stable and isolable salt of a tetracation, composed of four directly bonded cyclopropenylium rings, was synthesized by the direct reaction of l,2-bis(diisopropyl-amino)-3-lithiocyclopropenylium perchlorate (10) with tetrachlorocyclopropene. Apparently this tetracation is stabilized by the resonance contribution from the structures containing both the triafulvene- and radialene-type -conjugated systems. ... 

Similarly, the Iricyclopropylcyclopropenylium ion (23) reacted in chloroform with the tris(7/7-dibenzo[c ]fluorenylidenemethyl)methanide ion (24), which is known as the most stable allhydrocarbon carbanion, to give a covalent cyclopropene 25, which was directly observed by NMR spectroscopy but could exist only in solution evaporation or cooling of the chloroform solution of 25 afforded the heterolytically dissociated salt 23 24 quantitatively. In a polar solvent such as dimethyl sulfoxide the salt dissolved to give the free ions. As far as the reaction in tetrahydrofuran/acetonitrile was concerned, cyclopropenylium ions 26 (X = 4-Cl, H) reacted with carbanion 24 to give the covalent cyclopropene 27, whereas the slightly more stable cations 26 (X = 3-Me, 4-Me, 4-OMe) gave the completely ionized salts, the so-called hydrocarbon salts . The most stable cyclopropenylium ions 28 (pATr in 50 /o aqueous acetonitrile > 10) and 27 (pA t 8.9) also afforded the ionic salts under similar conditions. ... 

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