Rhodium cyclopropenones

In contrast, when allowed to react with Rh(CO)(PPh3)2(OTf) at 60-65°C, cyclopropenone forms cationic complex 17, in which cyclopropenone is bound to rhodium through the oxygen atom instead of the C-C double bond. Further heating at 60-65°C leads to the formation of the metal carbonyl insertion product 18 [34]. In refluxing benzene, 18 decomposes to diphenylacetylene and Rh(CO)(PPh3)2(OTf). 

Cyclopropenones reacted with iran -carbonylbis(triphcnylphosphane)rhodium trifluoro-methanesulfonate at 20 C to give the cationic complexes 4. In these compounds, the cyclo-propenone is bound to rhodium through the oxygen atom without opening of the three-mem-bered ring. ... 

Cyclopropenones reacted with chlorotris(triphenylphosphane)rhodium in benzene to form /ran.s-chlorocarbonylbis(triphenylphosphane)rhodium and acetylenes 2. ... 

Reaction of cyclopropenones with tra 5-chlorocarbonylbis(triphenylphosphane)rhodium gave l-rhodacyclopent-3-ene-2,5-diones 2 through the insertion of both the rhodium and the carbonyl into the three-membered ring. ... 

Alkyne insertion into the cyclopropenone C-C bond was catalyzed by [RhCl(CO)2]2 to give cyclopentadienones (Scheme 2.109) [166]. Rhodium(I)-NHC complexes also exhibited catalytic activity [167]. Benzyne can also participate in the reaction to provide indenone. 

A C—C (T-bond of a cyclopropenone 49 was added across an aryne, generated from 1,2-diiodobenzene and zinc, under rhodium catalysis, affording indenone 50 (Scheme 28.18) [24]. 

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