Amines reactions with cyclopropenones

The reaction of amines with cyclopropenones appears to be extremely sensitive to the reaction conditions Ammonia reacts with diphenylcyclopropenone at room temperature to yield the isomeric /3-lactams 56 and 57, whereas the vinyl aldehyde 58 is produced at — 33°C. These results can be rationalized in terms of the intermediate 59 which would result from conjugate addition of the nucleophile at carbon (equation 56). 

Cyclopropenyl imminium salts can be prepared by the reaction of cyclopropenones with substituted ammonium saltsor by the reaction of ethoxycyclopropenyl salts with amines The ease of rotation about the carbon-nitrogen double bond shows that the positive charge is not located solely on the nitrogen as in 67 but is shared with the cyclopropene ring as in 67a . 

Transformation of the disubstituted cyclopropenones I into aminocyclopropenylium salts 9 was accomplished by the reaction of a secondary amine, diisopropylamine, with the 3,3-di-chlorocyclopropenes 8, which were generated in situ from the cyclopropenones and thionyl chloride in dichloromethane. ... 

The reactions of cyclopropenones, in particular diphenyleyelo-propenone, with various amines have been investigated. Ammonia converts it into an azetidine at room temperature but gives a 3-amino-vinylaldehyde at lower temperatures [130-132] ... 

A superior route to many cyclopropenones appears to be the Favorskii-like reaction of a, a -dibromoketones with tertiary amines or potassium t-butoxide (equation 27) ... 

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