A Primary Nitroalkane to Carboxylic Acid Transformation

There has been great interest in recent years in methods for the generation of azomethine ylides and in exploitation of these reactive species in tandem/cascade processes for the rapid assembly of polyaza, polycyclic, multifunctional systems. a-Diazo ketones have featured greatly in such studies, treatment with a catalytic amount of rhodium(II) acetate generating transient rhodium carbenoids. A very common feature of many investigations of this type is the occurrence of quite unexpected reactions. For example, treatment of the diazo ketone 1 with a catalytic amount of 

Deduce the structure of the expected product from this reaction and suggest mechanisms for the conversion of 1 into 2,3 and 4. 

Pyrrolo[l,2-a]benzimidazoIe Synthesis by Ortho Nitro Interaction 

Suggest mechanisms which account for these observations. 

Reaction of the diarylbifuranylidenedione 1 with two equivalents of the stable ylide Ph3PCHCC 2Me in refluxing toluene under nitrogen for 24 hours gave a mixture of products, among which were the expected mono-Homer-Wittig ester 2 (26%) and the tricyclic product 3 (11%). 

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